Free Biotechnology Notes

2020-04-27T05:44:00.000-07:00

Biochemistry: the Molecules of Life

Explore the impact of biochemistry on bioenergy and health, discovering why graduates are in demand; with the Biochemical Society.

For those who are looking for introduction in biochemistry a great resource by University of East Anglia to enhance your knowledge about biochemistry principles.

starting on May 18, 2020. Register yourself :

https://www.futurelearn.com/courses/biochemistry/1

2020-04-02T02:48:00.000-07:00

Aeration, Agitation & its Kinetics

The majority of fermentation processes is aerobic and, therefore, requires the provision of oxygen. a microbial culture must be supplied with oxygen during growth at a rate sufficient to satisfy the organisms’ demand. The oxygen demand of an industrial fermentation process is normally satisfied by aerating and agitating the fermentation broth. However, the productivity of many fermentations is limited by oxygen availability and, therefore, it is important to consider the factors which affect a fermenter’s efficiency in supplying microbial cells with oxygen.

OXYGEN SUPPLY

Oxygen is normally supplied to microbial cultures in the form of air. The method varies with the scale of the process:

1. Laboratory-scale microbial cultures may be aerated by means of the shake-flask technique where the culture is grown in a conical flask shaken on a platform contained in a controlled environment chamber. Animal cell cultures are frequently grown in “T-flasks” which provide a large surface area for oxygen diffusion—the “T” referring to the total surface area available for cell growth; thus, a T-25 flask has a 25 cm2 growth area.

2. Microbial pilot- and industrial-scale fermentations are normally carried out in stirred, aerated vessels, termed fermenters. Laboratory scale experiments using culture volumes upward of approximately 500 cm3 are also performed in stirred, aerated fermenters as this enables the cultural conditions to be better monitored and controlled, and facilitates the addition of supplements and the removal of samples. Some fermenters are so designed that adequate oxygen transfer is obtained without agitation for example bubble columns and air-lift fermenters. Large-scale animal cell cultures have been grown in a range of fermenter types, including stirred aerated vessels based on microbial systems.

The rate of oxygen transfer from air bubble to the liquid phase may be described by the equation:

(1)

where C_L is the concentration of dissolved oxygen in the fermentation broth (mmoles dm^–3)

t is time (hours)

dC_L/dt is the change in oxygen concentration over a time period, that is, the oxygen-transfer rate (mmoles O2 dm^–3 h^–1)

K_L is the mass transfer coefficient (cm h^–1)

a is the specific gas/liquid interface area per liquid volume (cm² cm^–3)

C* is the saturated dissolved oxygen concentration (mmoles dm^–3).

K_L may be considered as the sum of the reciprocals of the resistances to the transfer of oxygen from gas to liquid, and the difference between the saturated dissolved oxygen concentration and the actual concentration in the fermentation broth (C*–C_L) may be considered as the “driving force” across the resistances. It is extremely difficult to measure both K_L and “a,” the gas–liquid interface area, in a fermentation and, therefore, the two terms are generally combined in the term K_La, the volumetric mass-transfer coefficient, the units of which are reciprocal time (h^–1). The volumetric mass-transfer coefficient is used as a measure of the aeration capacity of a fermenter. The larger the K_La, the higher the aeration capacity of the system.

DETERMINATION OF K_La VALUES

The determination of the K_La of a fermenter is essential in order to establish its aeration efficiency and to quantify the effects of operating variables on the provision of oxygen. Dissolved oxygen is usually monitored using a dissolved oxygen electrode which records dissolved oxygen activity or dissolved oxygen tension (DOT) while the equations describing oxygen transfer are based on dissolved oxygen concentration.The solubility of oxygen is affected by dissolved solutes so that pure water and a fermentation medium saturated with oxygen would have different dissolved oxygen concentrations yet have the same DOT, that is, an oxygen electrode would record 100% for both. The dissolved oxygen concentration, for all practical purposes, will be zero and the K_La may then be calculated from the equation: (where OTR is the oxygen transfer rate.)

(2)

OXYGEN-BALANCE TECHNIQUE

The K_La of a fermenter may be measured during fermentation by the oxygen balance technique which determines, directly, the amount of oxygen transferred into solution in a set time interval. The procedure involves measuring the following parameters:

1. The volume of the broth contained in the vessel, VL (dm³).

2. The volumetric air flow rates measured at the air inlet and outlet, Q_i and Q_o, respectively (dm³ min^–1).

3. The total pressure measured at the fermenter air inlet and outlet, P_i and P_o, respectively (atm. absolute).

4. The temperature of the gases at the inlet and outlet, T_i and T_o, respectively (K).

5. The mole fraction of oxygen measured at the inlet and outlet, y_i and y_o, respectively.

The oxygen transfer rate may then be determined from the following equation:

(3)

Where 7.32 × 10⁵ is the conversion factor equaling (60 min h^–1) [mole/22.4 dm³ (STP)] (273 K/l atm).

The K_La may be determined, provided that CL and C* are known, from Eq. 1

(4)

EFFECT OF AIRFLOW RATE ON K_La

Non Mechanically agitated reactors Bubble columns and air-lift reactors are not mechanically agitated and, therefore, rely on the passage of air to both mix and aerate.

1. Bubble columns

The flow pattern of bubbles through a bubble column reactor is dependent on the gas superficial velocity. At gas velocities of below 1–4 cm s^–1 the bubbles will rise uniformly through the medium and the only mixing will be that created in the bubble wake. This type of flow is referred to as homogeneous. At higher gas velocities bubbles are produced unevenly at the base of the vessel and bubbles coalesce resulting in local differences in fluid density. The differences in fluid density create circulatory currents and flow under these conditions is described as heterogeneous

The K_La in a bubble column is essentially dependent on the superficial gas velocity. for most non viscous situations the equation is:

(5)

Where V_s^c is the superficial air velocity corrected for local pressure. However, viscosity has an overwhelming influence on K_La in a bubble column that can be expressed as:

(6)

Where π is the liquid dynamic viscosity (N s m^–2).

2. Air-lift reactors

The difference between a bubble column and an air-lift reactor is that liquid circulation is achieved in the air-lift in addition to that caused by the bubble flow. The reactor consists of a vertical loop of two connected compartments, the riser and downcomer. Air is introduced into the base of the riser and escapes at the top. The degassed liquid is denser than the gassed liquid in the riser and flows down the downcomer. Thus, a circulatory pattern is established in the vessel—gassed liquid going up in the riser and degassed liquid coming down the downcomer. Circulation in an air-lift results in the bubbles being in contact with the liquid for a shorter time than in a corresponding bubble column. Thus, the K_La obtained in an air-lift will be less than that obtained in a bubble column at the same superficial air velocity, that is, less than 0.32 (V _s^c)^0.7 . The advantage of the air-lift lies in the circulation achieved, but this is at the cost of a lower K_La value.

Excerpts : Principles of fermentation technology, Stanbury & Whitaker

2020-04-01T09:33:00.003-07:00

Scintillation Counting

Liquid Scintillation Counting (LS Counting) is a lab based strategy that utilizes a Liquid Scintillation Counter (LSC) to check the radioactive emanations from a liquid sample. It is regularly utilized in the organic sciences to quantify the take-up of radioactive isotopes into biological materials. Radioactive isotopes interact with matter in two different ways, ionization and excitation.

Excitation drives an energized molecule or compound (known as a fluor) to emanate photons of light. The procedure is known as scintillation. when the light is recognized by a photomultiplier, it frames the premise of scintillation counting. Basically, a photomultiplier changes over the energy of radiation into an electrical sign, and the strength of the electrical signal that outcomes is legitimately corresponding to the energy of the first radioactive occasion. This implies two, or significantly more, isotopes can be independently identified and estimated in a similar example, if they have adequately different energy emitting spectra.

Types of scintillation counting

Solid scintillation counting

In solid scintillation counting the sample is placed adjacent to a solid fluor (e.g. sodium iodide). Solid scintillation counting is particularly useful for gamma emitting isotopes. This is because they can penetrate the fluor. The counters can be small handheld devices with the fluor attached to the photomultiplier tube or larger bench-top machines with a well-shaped fluor designed to automatically count many samples.

Liquid Scintillation Counting

In liquid scintillation counting, the sample is mixed with a scintillation fluid containing a solvent and one or more dissolved fluors. This method is particularly useful in quantifying weak b-emitters such as 3 H, 14C and 35S, which are frequently used in biological work. Scintillation fluids are called ‘cocktails’ because there are different formulations, made up of a solvent (such as Toulene) & fluors such as 2,5-diphenyloxazole (PPO), 1,4-bis(5- phenyloxazol-2-yl)benzene (nicknamed POPOP, or 2-(40 -t-butylphenyl)-5-(400-bi-phenyl)-1,3,4-oxydiazole (butyl-PBD).

Liquid Scintillation Counting

There are a number of physical processes that may disrupt LSC. These include:

Process	Explanation	Examples	Reduce Problem By
Chemiluminescence	Generation of light due to chemical processes.	Bleaching agents, dioxane-based scintillators	Equilibrate sample for a period of time in the LSC
Photoluminescence	Emission of photons from excited molecular species.	Vials, caps, other materials in the LSC. Some samples such as proteinaceous materials when dissolved in alkaline solubilisers such as hyamine.	Acidify samples; avoid exposure to sunlight or fluorescent lighting. Dark adapt samples for several hours before counting.
Quenching	Reduction in the scintillation count rate.	Photon quenching, chemical impurity quenching, colour quenching (see diagram below).	Use Internal Standards to account for quenching. A standard with a known CPM/DPM (Counts per minute/Disintegrations per minute) is added and measured and the reduction due to quenching adjusted for in the measured samples.

Examples of the use of LS Counting

Viral Proteins: Proteins produced by viruses when they infect a cell are produced in very small amounts and are difficult to detect and purify. If virus-infected cells are fed a radioactive amino acid, then each time that amino acid is linked to form the growing protein a radioactive ‘label’ is attached to the protein. This radioactive ‘label’ is then used to monitor the identification and purification of the viral protein. Amino acids containing ³H, ¹⁴C and ³⁵S are often used to label proteins. ³⁵S is particularly useful as sulphur is only found in two amino acids – methionine and cysteine.
Environmental Monitoring: Checking for ³H spills in the laboratory. Tritium is such a weak emitter that its presence cannot be detected by a Geiger-Mueller counter. Wipe testing is usually used. This is where suspect surfaces are wiped with a piece of tissue. The tissue is placed in LS Cocktail in a LS vial and counted in the LS Counter.

References:

1. Principles & Techniques of Biochemistry, 5th Edition. Keith Wilson & john Walker

2.http://simulab.ltt.com.au/5/Laboratory/StudyNotes/snLSCounting.htm

2020-03-30T09:05:00.000-07:00

COMPLEMENT SYSTEM

Complement System

The complement system refers to a series of >20 proteins, circulating in the blood and tissue fluids. Most of the proteins are normally inactive, but in response to the recognition of molecular components of microorganisms they become sequentially activated in an enzyme cascade – the activation of one protein cleaves and activates the next protein in the cascade enzymatically. Complement can be activated through three different pathways, each of which can cause the activation of C3, cleaving it into a large fragment, C3b, that acts as an opsonin, and a small fragment C3a (anaphylatoxin) that promotes inflammation. Activated C3 can trigger the lytic pathway, which can damage the plasma membranes of cells and some bacteria. C5a, produced by this process, attracts macrophages and neutrophils and also activates mast cells. Complement was discovered as a heat-labile component of normal plasma that causes the opsonisation and killing of bacteria.

Classical Pathway

This pathway involves complement components C1, C2 and C4. The pathway is triggered by antibody-antigen complexes binding to C1, which itself has three subcomponents C1q, C1r and C1s. The pathway forms a C3 convertase, C4b2a, which splits C3 into two fragments; the large fragment, C3b, can covalently attach to the surface of microbial pathogens and opsonise them; the small fragment, C3a, activates mast cells, causing the release of vasoactive mediators such as histamine.

Alternative Pathway

This pathway involves various factors, B, D, H & I, which interact with each other, and with C3b, to form a C3 convertase, C3bBb, that can activate more C3, hence the pathway is sometimes called ‘the amplification loop’. Activation of the loop is promoted in the presence of bacterial and fungal cell walls, but is inhibited by molecules on the surface of normal mammalian cells.

Mannose-binding Lectin Pathway

This pathway is activated by the binding of mannose-binding lectin (MBL) to mannose residues on the pathogen surface. This in turn activates the MBL-associated serine proteases, MASP-1 and MASP-2, which activate C4 and C2, to form the C3 convertase, C4b2a.

Role of Complement in Disease

The complement system plays a critical role in inflammation and defence against some bacterial infections. Complement may also be activated during reactions against incompatible blood transfusions, and during the damaging immune responses that accompany autoimmune disease. Deficiencies of individual complement components or inhibitors of the system can lead to a variety of diseases (Tabulated), which gives some indication of their role in protection against disease.

Table . Diseases associated with complement deficiencies

Complement Deficiency	Disease
C3 and Factor B	Severe bacterial infections
C3b-INA, C6 and C8	Severe Neisseria infections
Deficiencies of early C components C1, C4, C2.	Systemic lupus erythematosus (SLE)

REFERENCES:
Zaahira Gani, Cambridge, UK
https://www.immunology.org/public-information/bitesized-immunology/systems-and-processes/complement-system
https://www.youtube.com/watch?v=mfCeCvkQbuI&t=63s

FED BATCH KINETICS

2017-12-07T07:47:00.000-08:00

FED BATCH KINETICS

Fed Batch as the name indicates means batch cultures which need to be fed continuously, with medium without removing culture fluid. The culture broth is harvested usually only at the end of the operational period, either fully or partially (the remainder serving as the inoculum for the next repeated run). This process may be repeated (repeated fed-batch) a number of times if the cells are fully viable and productive. Thus, there are one or more feed streams but no effluent during the course of operation. Sources of carbon, nitrogen, phosphates, nutrients, precursors, or inducers are fed either intermittently or continuously into the culture by manipulating the feed rates during the run. The products are harvested only at the end of the run. Therefore, the culture volume increases during the course of operation until the volume is full. Thereafter, a batch mode of operation is used to attain the final results. Thus, the fed-batch culture is a dynamic operation. By manipulating the feed rates, the concentrations of limiting nutrients in the culture can be manipulated either to remain at a constant level or to follow a predetermined optimal profile until the culture volume reaches the maximum, and then a batch mode is used to provide a final touch. In so doing, the concentration of the desired product or the yield of product at the end of the run is maximized. This type of operation was first called a fed-batch culture or fed-batch fermentation.
The fed-batch culture has been practiced since the early 1900s, when it was recognized in yeast production from malt wort that the malt concentration in the medium had to be kept low enough to suppress alcohol formation and maximize the yield of yeast cells. High malt concentration would accelerate the cell growth, which in turn would cause anaerobic conditions that favored ethanol formation and lowered the yield of yeast cells. Additional wort was added at a rate that was always less than the rate at which the yeast cells could use it. Intermittent or incremental feeding of nutrients to an initially dilute medium was introduced thereafter in large-scale yeast production to improve the yeast yields while obviating the production of ethanol.4 However, there is some speculation that a small amount of ethanol may be necessary to ensure the quality of the baker’s yeasts.
The oldest and first well-known industrial application of a fed-batch operation was introduced after the end of World War I. It was the yeast cell production in which sugar (glucose) was added incrementally during the course of fermentation to maintain a low sugar concentration to suppress alcohol formation. The manufacture of yeast by fed-batch culture has gone through a series of improvements and is an industrially important fed-batch process. This process was historically followed by penicillin fermentation, in which the energy source (e.g., glucose) and precursors (e.g., phenyl acetic acid) were added incrementally during the course of fermentation8 to improve penicillin production. Prior to this practice, a slowly metabolized but more expensive substrate, lactose, was used in place of glucose in a batch culture. Oversupply of a carbon source resulted in more mycelial growth and low penicillin formation, while undersupply resulted in slower mycelial growth and, eventually, slower penicillin formation.
The primary candidates in the list of compounds that may be fed during the course of the operation include the limiting substrate, inducers, precursors, a carbon source, a nitrogen source, a phosphate source, inducers, and other nutrient sources. The feeding patterns are open loop or feedback controlled to maintain some key variables at constant optimum values such as the specific growth rate, respiratory quotient, pH, partial pressure of carbon dioxide, dissolved oxygen, substrate concentration, and some metabolite concentrations. The optimum feed rates sometimes require keeping these parameters to follow certain optimum profiles rather than keeping them at constant values. To maximize the cell formation rate for the case of constant cell mass yield, it is obvious that the substrate concentration should be maintained at the value that maximizes the specific growth rate, Sm, until the reactor is full. Therefore, it is also obvious that the initial substrate concentration should be Sm, that is, S(0) = Sm, and that the substrate concentration should be maintained at Sm throughout the course of fermentation. This will lead to the maximum cell concentration at the end of the run. To achieve this, the feed rate must be regulated properly to hold the substrate concentration constant at Sm. If it is not possible to set the initial substrate concentration to Sm for one reason or another, the substrate concentration should be brought to this value as soon as possible by applying at the beginning the maximum substrate feed rate (S(0) < Sm) or a batch period (S(0) > Sm) and then regulating thereafter to maintain the substrate concentration to remain at Sm until the fermentor is full. Once the fermentor is full, it is run in a batch mode to reduce the substrate concentration to a desired level, and the cells containing the product are harvested. This is the basis for the simplest case of a fed-batch culture.

Initial establishment of fed batch is in BATCH mode and then the feeding is done by applying one of several strategies.

lets see the strategies.... Quite interesting..uhmm

1.Use the same medium which you have used to establish the batch culture and add it. what will happen? increase in volume.. right???

2.Take the solution of limiting substrate; keeping concentration same as it was in initial medium & add it... again . tell me the result.... increase in volume... yes ! exactly..

Fed batch using above two strategies will be described as Variable Volume Fed Batch Culture

3.In this strategy concentrated solution of limiting substrate is to be added but at a rate less than no.1 & 2 strategy with the result is increase in volume.

Fed Batch employing above strategy is called as Intermediate Fed Batch Culture

4. This time a very concentrated solution of limiting substrate is added but at a rate less than strategy 1,2&3, resulting in overall increase in specific volume.

Fed Batch utilising above strategy is called as Fixed Volume Fed Batch Culture

So now we have an idea that what the heck is this fed batch strategy ..lets move on to the devilish part that is kinetics!!!! Start with Variable Volume Fed Batch culture

Variable Volume Fed Batch Culture

Pirt the king of kinetics ( That's what i call him......) , Dunn & Mor has developed this culture. I'm discussing Pirt's kinetics only. He said consider a batch culture in which growth is limited by concentration of one substrate; so whats the equation if we want to describe the biomass at any point of time::::

Equation for fed batch kinetics (variable volume)

Thus from above equation it may be concluded that input of substrate is compensated by substrate consumption. Thus ds/dt =0

Total biomass (X) concentration increases with time but cell concentration (x) remains constant, i.e. dx/dt = 0 and we can now write

μ= D

This situation is quasi steady state

(P.S. ::: please go back to basics of kinetics if you have trouble following above equation.. )

The difference between steady state in chemostat and quasi steady statein fed batch is that μ is constant in chemostat and it decreases in fed batch.

Fixed volume in next blog ....till then understand it and let me know if youy face any issues

CREDITS::: Whitaker, Pirt, Cambridge.

2014-08-14T19:58:00.000-07:00

Phagocytosis

Phagocyosis is the process of engulfment and digestion of microorganisms performed by macrophages & microphages.

The macrophages:

These cells originate from bone marrow promonocytes; after circulating in blood for few hours they migrate to tissues and constitute the mononuclear phagocyte system. They have been given specific names in accordance with their residing tissues; in lungs ; alveolar macrophages, in liver ; kupffer cells, microglial cells in brain, mesangial cells in kidney and in bone as osteoclasts.

Macrophages are capable of ingesting and digesting exogeneous antigens such a s whole microorganisms and insoluble particles and endogeneous matter such as injured or dead cells. Macrophages act by process of chemotaxis in which they get attract towards variety of substances. In the next step antigen adheres to the cell membrane of macrophage. Adherence induces the protrusions called Pseudopodia to extend around the attached antigen. Fusion of pseudopodia encloses the antigen with in membrane bound structure called Phagosome which then enters the phagocytic processing pathway. Here Phagosome fuses with the lysosome and makes phagolyosome. Lysome has hydrolytic enzymes which digest the ingested material. The digested contents are then released through the process of exocytosis.

It has been found that phagocytosis of antigen can be enhances many times in the presence of specific antibody; so antibody functions as opsonin; a molecule that binds to antigen and macrophage and enhance the process of engulfment. This whole process whereby antigens are rendered more susceptible to phagocytosis is called as opsonisation.

for further reads:::

kuby's immunology

RNA-laced bandages could treat the worst wounds on the genetic level

2013-06-19T07:45:00.000-07:00

couldn't help sharing this!!!
A breakthrough in RNA interference.
check it out!

http://io9.com/rna-laced-bandages-could-treat-the-worst-wounds-on-the-509956299

Proteases in leather Industry

2013-01-27T03:44:00.001-08:00

Proteases in leather Industry

Proteases belong to a group of proteolytic enzymes. They are obtained by microbial fermentations and are meant to use in leather industry for Dehairing, bating and soaking purposes. Their major use is in detergent industry too where they are used for breaking proteinaceous matter caused by body secretions, food stuffs and blood stains. These enzymes are obtained from plants, animals and microbial sources. Animal and Microbial Proteases from Fungi and bacteria re used in the pretanning processes of leather manufacture.

Animal Proteases are mixture of Trypsin, Chymotrypsin and various Peptidases which may contain amylase or lipase as secondary enzymes.

Proteases differ in their pH range as follows:

Acid Proteases: pH 2.5 – 6.0 derived from A. satoi

Alkaline Proteases: belong to group of serine proteases. More heat sensitive and heat

deactivate at 60⁰ C

Neutral Proteases: Obtained from Aspergillus and Penicillium spp.

Enzymes in Dehairing

Dehairing involves the digestion of basal cells of hair bulb and cells of malphigian layer. This is followed by loosening of hair with an attack on outermost sheath and breakdown of inner root sheath and parts of hair that are not keratinized.

Various Enzymes used in dehairing process are:

CLARIZYME: has been developed especially for dehairing of skins and hides. It is an alkaline protease derived from A. Flavus. It grows rapidly on wheat bran and produce large amount of protease.

Enzymes from bacteria have gained much importance because of commercial interest , easy production, high yield and easy recovery of enzyme. Examples are, Bacillus and Streptomyces spp.

Keratinases: hydrolyse Keratins are obtained from S. fradiae.

Enzymes in Soaking:

Soaking is the first operation where in hides and skins are cleaned and softened with water. Soaking is necessary for solubilisation and elimination of salts and globulin proteins contained within fibrous structures of hides and skins. It is carried out at alkaline conditions at temperature of 10-20⁰C.

Advantages of soaking are production of leather with less wrinkled skin.

Alkaline Proteases of Bacterial & Fungal origin has been used for soaking which reduces the need of chemicals.

Enzymes in Bating:

Bating is a process in which hides are softened by treating them in warm infusion of animal dung and product used for such purposes is called as BATE. Main objective of bating is to remove proteinaceous materials like albumin, globulins, mucoids from hides and skin and allow splitting up of collagen fibres to facilitate penetration of tanning materials and other chemicals, thereby giving finished leather with desired properties like feel, softness and pliability etc. Principal materials which a bate contains are proteolytic enzyme, a carrier for enzyme, wood flour and deliming agent like Ammonium chloride.

Enzymes from Aspergillus spp. are used in bating.

A combination of both mold and pancreatic enzymes are ideal bates.

Enzymes in Degreasing:

Degreasing is an essential step for production of glove and clothing leather. This process involves removal of excess natural fats from greasy skin. This grease results in defects like uneven dyeing, finishing and staining. Degreasing helps to obtain soft and pliable;e leather for garment manufacture.

It is carried out using aqueous emulsification with detergents or by solvent extraction since solvents are hazardous. So Lipase is used as an alternative for various solvents.

Acid Lipase from Rhizopus has been very effective in degreasing of sheep skins.

Fungal Lipase from A. Niger is also a good degreasing agent.

Alkaline Bacterial Lipase at pH of 9-9.4 is good for degreasing pig skin.

Enzyme (Cellulase ) Production

2013-01-26T03:59:00.000-08:00

CELLULASE PRODUCTION

Cellulase term is referred to all enzymes which cleave beta, 1-4 glycosidic linkages in cellulose. Many bacteria and fungi are celluloytic but preparations marketed for industrial applications are derived from Aspegillus niger, Neurospora and Trichoderma viridae. Aspergillus enzyme exerts good activity on CMC (carboxy methyl cellulose) but fails to attack on solid cellulose because it lacks a important component i.e. C₁ Cellulase. Cellulase is multienzyme complex with 2 important components called C₁ and C_x. Both have important functions.

C₁can attack upon native cellulose of higher crystallinity while C_x cannot attack such kind of cellulose but can split in turn the cellulose fragments which have been derived by action of C_1.

Trichoderma produces an enzyme complex with high levels of C₁ cellulase which extensively degrades insoluble cellulose.

Cultivation & Purification

In large scale fermentation A. niger is mostly cultured by wheat bran tray method. This process yields high levels of enzyme. Extraction of cellulose from solid substrate cultures is performed by percolation of dried mold bran with 0.02 to 0.1 M lactic acid.

Neurospora and Trichoderma are grown by submerged culture. For continuous culture it is advantageous that T. Viride produces a suspension of short mycelia threads, rarely forming pellets. For submerged cultivations bran and wheat straw pre-treated with alkali can be used as a source of cellulose. Ammonium ions can be used a suitable nitrogen source. A correct pH profile is necessary to give optimum enzyme yields in batch culture concentration and purification of enzyme is carried out by precipitation, adsorption and gel filtration techniques.

Ammonium sulphate is used for precipitation followed by centrifugation at 10,000 g for 10 minutes. After separating the sediment supernatant is subjected to re centrifugation for 10,000 g for 10 minutes. Precipitates are suspended in 0.5 M acetate buffer with pH 5 and crystallisation procedures are followed.

Industrial Uses

Ø Cellulase is currently used to improve texture and palatability of poor quality vegetables.

Ø It also accelerates drying of vegetables.

Ø A potential use of cellulose is conversion of cellulosic material to glucose and other sugars which in turn can be used as microbial substrates in variety of fermentations e.g. Alcohol.

Computer Applications in Fermentation Technology

2012-05-04T22:41:00.001-07:00

Computer Applications in Fermentation Technology

The use of computers for for modelling fermentation processes started in 1960s. Initially the use of computers was restricted because of the cost factor but reductions in the cost and the availability of the cheaper small computers has widened interest in their possible applications. The availability of efficient small computers has led their use for pilot plants and laboratory systems because the financial costs for the online computer systems counts the insignificant part of the whole system. There are three distinct systems areas of computer function postulated by Nyiri in 1972:

a) Logging of Process Data: This is performed by the data acquisition which has both hardware and software components. there is an interface between the sensors and the computer. the software should include the computer program for sequential; scanning of the sensor signals and the procedure of data storage.

b) Data Analysis: Data reduction is performed by the data analysis systems which is acomputer program based on a series of mathematical equations. the analysed information may be put on a print out, fed into data bank or utilized for process control.

c) process control: is also performed by a computer program. signals from the computer are fed tio the pumps, valves or switches via the interface. in addition to this computer program may contain instructions to display devices or teletypes to indicate alrms.

Components of Computer Linked system:

When a computer is linked to a fermenter to operate as a control and recording system, a number of factors must be considered to ensure taht all the components interact and function satisfactorily for the control a d data logging.An example is DDC (Direct Digital Control) system to explain the computer controlled addition of a liquid from a resrvoir to a fermenter.

A simple outline of the main components is as follows:

Sensor S in fermenter produces a signal which may need to be simplified and conditioned in the correct analogue form. at this stage it is necessary to convert the signal to a digital form which can be subsequently transmitte dto the computer. An interface is placed in the circuit at this point. The interface serves as the junction point for the inputs from the fermenter sensors to the computers and output signals from the computer to the fermenter controls such as a pump T attached to an additive reservoir.

A sensor will generate a small voltage proportional to the parameter it is going to measure. for example a temperature probe might generate 1V at 10^oC and 5V at 50^oC. But this signal cannot be understood by the computer and must be converted from an analogue to digital converter ( ADC) into digital form.

The accuracy will depend upon the number of bits it sends to the computer. AN 8-bit converter will work in the range of 0-255 and it is tehrefore able to divide a signal voltage into 256 steps. This will give amaximum accuracy of 100/256, which is pproximately 0.4%. However a 10- bit converter can give 1024 steps with a n accuracy of 100/1024, which is pproximately 0.1%. therefore when a parameter is to be monitored very accurately a converter of the appropraite degree of accuracy will be required. the time taken for an ADC to convert voltage signals to a digital output will vary with accuracy, but improved accuracy will lead to slower conversion and hence slower control responses. The small computers is often used for one or more fermenters. it is coupled to a real time clock, which determines how frequently readings from teh sensor should be taken and possibly recorded. Ancillary equipments include a VDU, a data store , a teletype, a graphic display unit, a print out, alarms and barometer.

It is also possible to develop online programs so that online instruments can be checked regularly and recalibrated when necessary.

P.S.

Next post will be about the details of three distinct areas.
<p><span style="display:none">sciseekclaimtoken-4fc587626eac4</span></p>

Most Astounding Fact About The Universe

2012-03-05T18:44:00.000-08:00

http://thenextweb.com/shareables/2012/03/06/the-most-outstanding-fact/

INDUSTRIAL ALCOHOL PRODUCTION

2012-03-01T18:40:00.002-08:00

Industrial Alcohol
The production of industrial alcohol, ethanol become commercially feasible on a large scale after 1906 when the Industrial Alcohol Act was passed. This act allowed the sale of tax-exempt alcohol, if it has first denatured to prevent its use in various Alcohol beverages. Industrial Alcohol is commonly employed as a solvent and to a lesser extent as a raw material for chemical synthesis. Smaller amounts are also used as a motor fuel like gasoline.
Microorganism:
Choice of fermentation microorganism for the alcohol production depends upon the type of carbohydrate employed in the medium. For example if starch and sugar are raw materials in the medium then specially selected strains of Saccharomyces crevisiae are utilized. Production from Lactose of whey is accomplished with Candida pseudotropicalis. If it is sulfur waste liquor fermentation the Candida utilis is the best organism, because of its ability to ferment pentoses. So particular strains of these various organisms actually employed for the fermentation are selected for several properties. They must grow rapidly, have higher tolerance to the high concentartions of sugar but at the same time they must be able to produce much larger amounts of alcohol and be resistant to the produced alcohol.
Media
The media for the commercial production includes:
Blackstrap Molasses / Corn (Blackstrap molasses has greater use)
Grains
Sulfite waste liquor
Whey
Patatoes
Wood Wastes

For Molasses fermentation , molasses must be diluted with water to a sugar conc. between 10 -18%. Concentrations greater than 20% are not employed as they could be detrimental to yeast. The pH of the medium is set between 4 -5 by adding sulfuric acids or lactic acids, or by employing Lactic acid bacteria to bring initial lactic acid fermentation. Microbial contaminants are usually inhibited by the low pH, high sugar conc. and anaerobic conditions of the fermentation and by the high alcohol production by the yeast.
Starchy media such as corn, rye and barley must undergo initial starch hydrolysis. This can be accomplished by mashing with barley malt, by addition of dilute acids or by utilizing fungal amylolytic enzymes (Aspergillus and Rhizopus).In most of the cases, malt is used to accomplish hydrolysis of starch By mixing 30% barley and 70% corn with water and carry on the mashing procedures similar to the wine or nbeer making procedures.
Fermentation:
Fermentation is carried out in large reactors at a temperature between 21 - 27^oC, but heat evolution might raise the temperature to 30^oC, so cooling coils are used to bring the temperature down. Fermentation lasts for about 2-3 days, but actual time period depends upon the substrate utilized and temperature. The fermentation broth at completion of fermentation ranges from 6 -9 percent alcohol by volume and this alcohol reflects the yield 0f 90 -98% theoretical conversion of substrate sugar to alcohol.So yileds should not be confused with "proof" as proofing means alcohol concentartion designation and it will be twice the percentage in vol of ethanol as dissolved in water e.g. 70% ethanol is 140 proof.

FERMENTATION ECONOMICS

2012-03-01T03:02:00.002-08:00

Fermentation Economics:

The objective of any successful fermenttaion process is the ability to produce a fermentation product. Thus the product must be sold to recover all the costs along with desired profit. But manufacturing should be done in accordance with the market demand. So there could be 2 possibilities:

First possibilty is : That the market for so called product already exist because the same or similar product has previously been sold by others.

Second possibilty is : a newly manufactured or discovered product e.g. a new antibiotic will require a market to be established.

This might include the approval by FDA ( food and drug adminstration)

There are certain obstacles regarding the marketing of a certain product like the semand of the product is low or it has relatively very few uses.so its quite obvious that for a product lke this it could be challenging to get patent coverage because of lack of utility.

for the products which are already in the market , there could be a fierce competition. so to succed in the competition the product must be cheap enough that it can be sold at or slightly less than the already existing selling price. So, in the nutshell, the whole fermentation process and its product must be able to compete on an economically sound basis with the similar products in the market.

The economic position of a fermentation product is closely tied to the costs associated with its production and distribution. These costs can be categorised into several classes as follows:

Media components:

The competitive postion and expected profits from a fermentation product are closely tied to the costs of the various components of the production medium. usually inoculum medium is less expensive because it is required to provide rapid cell growth only and not for converting large amount of carbon substarte into a fermentation product. However any medium component may be subject to fluctuations in context to availabilty and costs. so it is always advantageous to have a alternative medium for use if any unusual situation happens.

Labor Costs:

labor costs involve technical ad non technical trained personnel at all levels of competence. This includes handling of cultures, inoculum, production, product recovery and purification, packaging, cleaning and adminstartion and so forth. Labor costs vary from fermentation to fermentation.

Contamination and sterlization:

Contamination always add costs to any fermentation process. most fermentations cannot survive serious conmtaminations so the medium must be discardedmodertae fermentations does not require the medium to be discarded but it might affect the yields. Certain fermentations are more prone to contamination than others. This involves cases in which foaming is a problem. some are more sensitive to phage infections like bacterial fermentations. So there has to be an alternate method for the contaminant growth. Such methods include low pH of the medium, partial heat treatment of the medium and inclusion of certain chemicals so a sto retad contaminant growth.

Yield and Product Recovery:

Product Yield and Recovery are the prime considertaions of fermentation economics and in that context yield and recovery must be considered together, since high yield id of little value if the product cannot be recovered properly for sale.

Product Purity:

At one end of the scale some products, like antibiotic preprations must be sterile and free from pyrogens. In contrast other antibiotic preprations are sold in crude form for mixture with animal feeds. Thus the purity level required for the marketing of a fermentation product has a major effect on the costs associated with the product.Specific fermentation products can also be marketed at more than one concentartion as level of purity. For example, lactic acid is sold at strengths ranging from approx 20 - 85% and its purity levels range from crude technical grade to high purity edible and U.s.P. grades. Each of these grades of lactic acid has a place on the market.

Waste Disposal:

Costs attributed to waste disposal vary from minimal to maximal factor in fermentation process. A critical consideration is the acceptance of waste by Municipal's STW (Sewage Treatment Works); as they might want pre treatment of wastes before the acceptance. In the altter case the fermentation company must have its own waste treatment plant. Disposal of wastes is no longer simple in contrsat to historical disposal in the rivers, streams or other water bodies. Certain fermentations require the waste to be sterlized before disposal.

Research Costs:

Fermentation process must include those expenses incurred in the research that actually discovered the process nad developed it. These costs can be considerable for those fermentations where they provide new products .there are less tangible research costs that must also be considered in the overall cost of fermentation. This type of reserach is pursued in teh hope that teh resulting basic information obtained on the growth and synthetic activities of microbes will be of later value in defining areas of exploration and approaches for discovering new fermentation processed and bettering old processes.

An appraisal of the economic potential is required for the fermentation process which evaluate all the above categories under present and future market protential. but evaluation must be made as early as possible during process development. Also process must be evaluated at later stages during actual production. It is also important to consider present and future costs and a selling price for the product that market can bear.. All these points must be evaluated and then decide whether the fermentation product can be sold at an acceptable level of profit or not? If the decisons are negative then the alternatives are to abandon the whole process and carry out further reesarch on the product recovery. After all a great deal of money is at stake in these decisons!!!

Reference: Casida, L.E. Industrial Microbiology

Media Sterlization

2012-02-12T07:04:00.000-08:00

Media Sterlization:

Media can be treated by variety of methods like radiations, filtration, ultrasonic treatment and heat. Practically the universal and most favourable method for sterilization is the steam.

Kinetics of Sterlization:

The destruction of microorganisms by steam or the moist heat can be described by the first order chemical reaction and can be represented by the following equation:

- dN / dt = kN Eq no. 1

N is no. Of viable organisms present

t is the time of sterilization treatment.

k is the reaction rate constant or the specific death rate

Upon integration of equation no.1 we get:

N_t / N₀ = e ^–kt Eq no. 2

N₀is no. of viable organisms presentat the start of sterilization

N_tis the no. Of viable organisms after treatment period t

Upon taking natural logarithms of the Eq. No. 2 we get:

ln (N_t/ N₀) = -kt Eq no.3

A plot of natural logarithm of N_t/ N₀against time will yield a straight line ; the slope of which is equalto – k (see the fig. ABOVE)

So we can make 2 anomalous predictions from the plot:

1. An infinite time is required to achieve sterile conditions. ( Nt = zero)

2. After a certain period of time there will less than one viable cell present.

But the above plots can be observed only when the sterilization of pure culture is done in one physiological form only and that too under the ideal sterilization conditions. Thus, the value of k is not only species dependent but also on the physiological form of the cell e.g. endospores of genus Bacillus will be more heat resistant than the vegetative cells.

Considering this factor Richards in 1968 has produced a series of graphs (see Graphs below) which illustrate the deviation from the theory which can be expressed in the practice.

GRAPH 1

GRAPH 2

Above 3 graphs illustrate the effect of time of heat treatment on the survival of a population of bacterial endospores.

Graph 1 shows the initial population increase resulting from heat activation of spores in early stages of sterilization; followed by the decline in viable spore number. Activation o spores is significantly more than their destruction during early stages of the process and therefore viable number of spores increases before the observation of exponential decline.

Graph2 illustrates the initial stationary period followed by the decline; owing to the fact that the death of the spores is compensated by the heat activation of spores.

Graph 3 shows the population decline at a sub maximum rate due to the death of the spores.

GRAPH 3

Now we know that with any first order reaction, the reaction rate increases with temperature increase due to increase in the reaction rate constant which is the case of destruction of microorganisms (i.e.specific death rate constant; k).

Thus, the relationship between the temperature and reaction rate constant can be expressed by Arrhenius Equation:

dlnk/dT = E/RT²Eq no 4:

E is the Activation energy

R is gas constant

T is absolute temperature

Upon integration of Eq. no 4 we get:

k= Ae^{- E/RT}Eq. no 5:

A is Arrhenius constant

On taking natural Logarithms Eq no. 5 becomes:

ln k = ln A - E/Rt Eq. No.6:

By combining Eq. no. 3 and 5 following expression can be derived for heat sterilization of a pure culture at a constant temperature:

ln (N_t/ N₀) = A.t.e ^–E/Rt Eq. no. 7

Deindoerfer and Humphery used the term ln (N_t/ N₀) as a design criterion for the sterilization which has been called as DEL Factor or NABLA factor.

Del factor is a measure of fractional reduction of viable organism count produced by a certain heat and time regime. Therefore:

∇ = ln (N_t/ N₀₎

But; ln (N_t/ N₀₎ = kt

& kt = A.t. e ^–E/Rt

Thus, ∇ = A.t. e ^–E/Rt Eq. no. 8

On rearranging equation no. 8 becomes :

ln t = E/RT + ln ( ∇ /A) eq. no 9

Thus, a plot of the natural logarithm of the time required to achieve a certain ∇ value against the reciprocal of the absolute temperature will yield a straight line, the slope of which is dependent on the activation energy.( see fig below)

So a regime of time and temperature can be determined if we want to achieve the desired Del factor. However , as we know fermentation medium is not an inert mixture of components so it is very likely that deleterious reactions occur , resulting in loss of nutrient quality. Two types of reactions occur during sterilization as follows:

(i) Interactions between nutrient components of the medium. A common occurrence during sterilization is the Maillard-type browning reaction which results in discoloration of the medium as well as loss of nutrient quality. These reactions are normally caused by the reaction of carbonyl groups, usually from reducing sugars, with the amino groups of amino acids and proteins. Problems of this type are normally resolved by sterilizing the sugar separately from the rest of the medium and recombining the two after cooling.

(ii) Degradation of heat labile components. Certain vitamins, amino acids and proteins may be degraded during a steam sterilization regime. In extreme cases, such as the preparation of media for animal-cell culture, filtration may be used.

P.S I do not owe any of the above text.

References:

Shuler, M.L. and Kargi, F. (2002) Bioprocess Engineering: Basic Concepts. 2 nd Edition. Prentice Hall,

Stanbury, P. , Whittaker, A. (2004) Principles of Fermentation Technology

Facts About DNA

2012-02-06T06:02:00.000-08:00

Facts About DNA

DNA stands for deoxyribonucleic acid.
DNA is part of our definition of a living organism.
DNA is found in all living things.
DNA was first isolated in 1869 by Friedrich Miescher.
James Watson and Francis Crick figured out the structure of DNA.
DNA is a double helix.
The structure of DNA can be likened to a twisted ladder.
The rungs of the ladder are made up of “bases”
Adenine (A) is a base.
Thymine (T) is a base.
Cytosine (C) is a base
Guanine (G) is a base.
A always pairs with T in DNA.
C also pairs with G in DNA.
The amount of A is equal to the amoun tof T, same for C and G.
A+C = T+G
Hydrogen bonds hold the bases together.
The sides of the DNA ladder is made of sugars and phosphate atoms.
Bases attached to a sugar; this complex is called a nucleoside.
Sugar + phosphate + base = nucleotide.
The DNA ladder usually twists to the right.
There are many conformations of DNA: A-DNA, B-DNA, and Z-DNA are the only ones found in nature.
Almost all the cells in our body have DNA with the exception of red blood cells.
DNA is the “blueprint” of life.
Chromosomal or nuclear DNA is DNA found in the nucleus of cells.
Humans have 46 chromosomes.
Autosomal DNA is part of chromosomal DNA but does not include the two sex chromsomes – X and Y.
One chromosome can have as little as 50 million base pairs or as much as 250 million base pairs.
Mitochondrial DNA (mtDNA) is found in the mitochondria.
mtDNA is only passed from the mother to the child because only eggs have mitochondria, not sperm.
There’s a copy of our entire DNA sequence in every cell of our body with one exception.
Our entire DNA sequence is called a genome.
There’s an estimated 3 billion DNA bases in our genome.
One million bases (called a megabase and abbreviated Mb) of DNA sequence data is roughly equivalent to 1 megabyte of computer data storage space.
Our entire DNA sequence would fill 200 1,000-page New York City telephone directories.
A complete 3 billion base genome would take 3 gigabytes of storage space.
If unwound and tied together, the strands of DNA in one cell would stretch almost six feet but would be only 50 trillionths of an inch wide.
In humans, the DNA molecule in a non-sex cell would have a total length of 1.7 metres.
If you unwrap all the DNA you have in all your cells, you could reach the moon 6000 times!
Our sex cells–eggs and sperm–have only half of our total DNA.
Over 99% of our DNA sequence is the same as other humans’.
DNA can self-replicate using cellular machinery made of proteins.
Genes are made of DNA.
Genes are pieces of DNA passed from parent to offspring that contain hereditary information.
The average gene is 10,000 to 15,000 bases long.
The segment of DNA designated a gene is made up of exons and introns.
Exons have the code for making proteins.
Introns are intervening sequences sometimes called “junk DNA.”
Junk DNA’s function or lack thereof is a source of debate.
Part of “junk DNA” help to regulate the genomic activity.
There are an estimated 20,000 to 25,000 genes in our genome.
In 2000, a rough draft of the human genome (complete DNA sequence) was completed.
In 2003, the final draft of the human genome was completed.
The human genome sequence generated by the private genomics company Celera was based on DNA samples collected from five donors who identified themselves only by race and sex.
If all the DNA in your body was put end to end, it would reach to the sun and back over 600 times (100 trillion times six feet divided by 92 million miles).
It would take a person typing 60 words per minute, eight hours a day, around 50 years to type the human genome.
If all three billion letters in the human genome were stacked one millimeter apart, they would reach a height 7,000 times the height of the Empire State Building.
DNA is translated via cellular mechanisms into proteins.
DNA in sets of 3 bases, called a codon, code for amino acids, the building blocks of protein.
Changes in the DNA sequence are called mutations.
Many thing can cause mutations, including UV irradiation from the sun, chemicals like drugs, etc.
Mutations can be changes in just one DNA base.
Mutations can involve more than one DNA base.
Mutations can involve entire segments of chromosomes.
Single nucleotide polymorpshisms (SNPs) are single base changes in DNA.
Short tandem repeats (STRs) are short sequences of DNA repeated consecutively.
Some parts of the DNA sequence do not make proteins.
Genes make up only about 2-3% of our genome.
DNA is affected by the environment; environmental factors can turn genes on and off.
There are many ways you can analyze your DNA using commercially available tests.
Paternity tests compare segments of DNA between the potential father and child.
There are other types of relationship testing that compares DNA between siblings, grandparents and grandchild, etc.
DNA tests can help you understand your risk of disease.
A DNA mutation or variation may be associated with a higher risk of a number of diseases, including breast cancer.
DNA tests can help you understand your family history aka genetic genealogy.
DNA tests can help you understand your ethnic make-up.
DNA can be extracted from many different types of samples: blood, cheek cells, urine.
DNA can be stored either as cells on a cotton swab, buccal brush, or frozen blood or in extracted form.
In forensics, DNA analysis usually looks at 13 specific DNA markers (segments of DNA).
The odds that two individuals will have the same 13-loci DNA profile is about one in one billion.
A DNA fingerprint is a set of DNA markers that is unique for each individual except identical twins.
Identical twins share 100% of their genes.
Siblings share 50% of their genes.
A parent and child share 50% of their genes.
You can extract DNA at home from fruit and even your own cheek cells.
DNA is used to determine the pedigree for livestock or pets.
DNA is used in wildlife forensics to identify endangered species and people who hunt them (poachers).
DNA is used in identify victims of accidents or crime.
DNA is used to exonerate innocent people who’ve been wrongly convicted.
Many countries, including the US and UK, maintain a DNA database of convicted criminals.
The CODIS databank (COmbined DNA Index System) is maintained by the BI and has DNA profiles of convicted criminals.
Polymerase chain reaction (PCR) is used to amplify a sample of DNA so that there are more copies to analyze.
We eat DNA every day.
DNA testing is used to authenticate food like caviar and fine wine.
DNA is used to determine the purity of crops.
Genetically modified crops have DNA from another organism inserted to give the crops properties like pest resistance.
Dolly the cloned sheep had the same nuclear DNA as its donor mom but its mitochondrial DNA came from from the egg mom. (Does that make any sense?)
People like to talk about DNA even if it bears no relation to science or reality.
A group of bloggers who write regularly about DNA and genetics have banded to gether to form The DNA Network.
Lists about DNA can get a little boring.

INTERESTING????

GET MORE INFO HERE EYEONDNA.COM

AMAZING PHENOMENON OF SAND CASCADES ON MARS

2012-02-04T06:25:00.000-08:00

Dark Sand Cascades on Mars

They might look like trees on Mars, but they're not. Groups of dark brown streaks have been photographed by the Mars Reconnaissance Orbiter on melting pinkish sand dunes covered with light frost. This image was taken in 2008 April near the North Pole of Mars. At that time, dark sand on the interior of Martian sand dunes became more and more visible as the spring Sun melted the lighter carbon dioxide ice. When occurring near the top of a dune, dark sand may cascade down the dune leaving dark surface streaks -- streaks that might appear at first to be trees standing in front of the lighter regions, but cast no shadows. Objects about 25 centimeters across are resolved on this image spanning about one kilometer. Close ups of some parts of this image show billowing plumes indicating that the sand slides were occurring even when the image was being taken.

Image Credit: HiRISE, MRO, LPL (U. Arizona), NASA

WINE PRODUCTION

2011-12-14T06:48:00.000-08:00

WINE PRODUCTION

Wine is the product of grapes which can be obtained after alcoholic fermentation by yeast. Technically it is the transformation of sugars of grapes by yeast under anaerobic conditions into carbon dioxide, ethanol and some by products. Wine can also be produced by the fermentation of the fruit juices, honey and berries.

a) Wine from Grapes: Basically two types of grapes: Red and white ones are used for production of 2 different types of wines; namely RED WINE AND WHITE WINE. Grapes with a sugar content of 15- 20% are appropriate for extraction after harvesting. Whole process involves stemming, cleaning, crushing followed by addition of sodium or potassium meta-bisulphite to check the growth of undesirable organisms. Crushed grapes so obtained are known as MUST.

b)Fermentation: Fermentation is carried out by adding 2-5% of wine yeast namely: Saccharomyces crevisiae in the MUST. The contents should be mixed twice a day by punching the cap of floating grapes so as to allow the profuse growth of yeast due to increase in aeration. This step helps in extraction of colour. Thereafter mixing should be stopped and anaerobic fermentation is carried out by maintaining temperature at 24-27⁰C for about 3-6days (in case of red wine) and around 10 – 20⁰C for about 4-12 days (in case of white wine).

c)Recovery: Once the fermentation is completed the fermented juice is drawn off and stored under the atmosphere of CO₂for further fermentation for about 7 – 12 days temperature of 21-29⁰C.

Thereafter wine is pasteurized before aging. During pasteurization the protein is precipitated and removed. After filtering the wine is transferred in the wooden tanks. It is believed that aging is important for imparting flavour, aroma, sanctity and colour to the wine. After aging wine is ready to clarify and then it is bottled.

PRIMARY AND SECONDARY METABOLITES

2011-12-06T22:32:00.001-08:00

PRIMARY & SECONDARY METABOLITES

The metabolism can be defined as the sum of all the biochemical reactions carried out by an organism. It involves two pathways: Primary metabolic pathways (PMPs) produce too few end products while secondary metabolic pathways (SMPs) produce too many products.

PMPs require the cell to use nutrients in its surroundings such as low molecular weight compounds for cellular activity. There are three potential pathways for primary metabolism: the Embden Meyerhof-Parnas Pathway (EMP), the Entner-Dourdorof pathway and the hexose monophosphate (HMP) pathway. The EMP pathway produces two molecules of pyruvate via triose phosphate intermediates. This pathway occurs most widely in animal, plant, fungal, yeast and bacterial cells. Many microorganisms however use this pathway solely for glucose utilization. During primary metabolism hexoses such as glucose are converted to single cell protein (SCP) by yeasts and fungi. Yeasts from the Sachcharomyces species produce alcohol as cells grow during the log phase using an anaerobic primary metabolic pathway. This account for most of the alcohol found in nature and is widely used in the fermentation industry to produce beer, wine and spirits.

For example in the citric acid fermentation process involving Aspergillus Niger, hexoses are converted via the EMP pathway, to pyruvate and acetyl Co-A which condenses with oxaloacetate to form citrate in the first step of the TCA cycle. Ethanol, lactic acid and acetic acid were the first commercial products of the fermentation industry. Several of these products have applications as alternative energy sources, for example alcohol has been used to produce a cheaper alternative to petrol in developing countries such as Brazil and in Europe between World Wars I and II.

Secondary metabolism synthesises new compounds. Secondary metabolites are not vital to the cells survival itself but are more so for that of the entire organism. Relatively few microbial types produce the majority of secondary metabolites. Secondary metabolites are produced when the cell is not operating under optimum conditions e.g. when primary nutrient source is depleted. Secondary metabolites are synthesized for a finite period by cells that are no longer undergoing balanced growth. A single microbial type can produce very different metabolites. Streptomyces griseus and Bacillus Subtillus each produce more than fifty different antibiotics. Most secondary metabolites are produced by families as closely related compounds. The chemical structure and their activities cover a wide range of possibilities, including antibiotics, ergot alkaloids, naphtalenes, nucleosides, peptides, phenazines, quinolines, terpenoids and some complex growth factors. The production of economically important metabolites such as antibiotics by microbial fermentation is one of the major activities of the bioprocess industry.

Secondary metabolites such as penicillin are produced during the stationary phase (idiophase) of cell growth. Most of the knowledge concerning secondary metabolism comes from the study of commercially important microorganisms.

There are some similarities between the pathways that produce primary and secondary metabolites, namely that the product of one reaction is the substrate for the next and the first reaction in each case is the rate-limiting step. Also the regulation of secondary metabolic pathways is interrelated in complex ways to primary metabolic regulation.

Primary Metabolites

Fermentation products of primary metabolism such as ethanol, acetic acid, and lactic acid were the first commercial products of the fermentation industry. These industrial revelations were soon followed by citric acid production along with other products of fungal origin. Due to the high product yield and the low reproducibility costs, major interest has been shown in the respective markets. Production of cell constituents i.e. lipids, vitamins, polysaccharides as well as intermediates in the synthesis of cell constituents such as amino acids and nucleotides are also of great economic importance in present-day industry. The effectiveness of yeasts along with other microorganisms as sources of the B-group vitamins has been recognized for more than 50 years and like products of catabolic primary metabolism e.g. ethanol, citric acid etc. are of great commercial importance.

Citric acid is an organic acid that is of major economic use in today’s industry. It is a very important commercial product and is widely used in the food and beverage industries as a food additive. In addition to the beverage and food industry, citric acid is used in effervescent powders as well as being used in boiler and metal cleaning. Factors effecting citric acid production vary considerable and depend predominantly on the strain of A. niger used. Other factors that affect citric acid production include the type of raw material fermented, the amount of methyl alcohol present, the substrate’s initial moisture content as well as the fermentation time and temperature. Much research has been conducted over the years in order to increase the yield of citric acid production.

Nucleotides are used in the preparation of poly and oligonucleotides as well as being of potential nutritional and medical interest. However the greatest interest in nucleotides lies in the fact that they have the ability to enhance the flavour of foods. Yeast extract is extensively used as a flavouring agent in the food industry and is widely available either in powder or paste form. After autolysis and partial hydrolysis of RNA, ribonucleotides such as 5’-monophpsphate (GMP) and inosine 5’-monophosphate (IMP) may be extracted from the biomass. Flavour enhancement is a property of these purine ribonucleosides as well as the ribonucleoside, xanthylic acid (XMP). These food enhancers are responsible for meaty flavours found in foods and are available on the market worldwide. These products are of major importance in the food industry and currently international trade surpasses US $1.1 billion per year (23).

Secondary Metabolites

Antibiotics were first defined as a chemical compound produced by a microorganism, which has the capacity to inhibit the growth of and even destroy bacteria and microorganisms in dilute solutions. Sir Alexander Fleming first discovered the antibiotic properties of the mould Penicillin notatum in 1929 at St. Mary’s hospital in London, when he noticed that Penicillin

notatum destroyed a staphylococcus bacterium in culture. Penicillin is bactericidal to a number of gram-positive bacteria and acts by inhibiting transpeptidation thus preventing new cells from forming walls. It belongs to the beta-lactam family of antibiotics. During World war two research was moved to the USA where large-scale growth of the mould began. Firstly penicillin moulds were grown in small shallow containers on nutrient broth. Methods of growth were improved by using deep fermentation tanks with continuous sterile air supply and corn steep liquor as a source of nutrients. In 1943 a cantaloupe mould, P. Chysogenum was found to produce twice the amount of penicillin than P. notatum. Since then researchers continued to find higher yielding penicillin moulds and have also improved yields further by exposing moulds to x-rays and UV light. The first type of penicillin produced was Penicillin G, which had to be administered to patients parenterally because it is broken down by stomach acid. Penicillin V was later formulated so that it could be taken orally; unfortunately it was less active than Penicillin G.

The enhancement of antibiotic industrial yield has been achieved through traditional strain improvement programs based on random mutation and screening. Recombinant DNA techniques have existed since the 1970’s and involve the introduction of DNA fragments into host cells using a vector (a plasmid or phage) that contains a selection marker. The DNA fragments are integrated into the host genome or autonomously replicated as a plasmid. Transformants are then screened for improved characteristics. The pharmaceutical company Eli Lilly was responsible for the first recombinant DNA improvement of an antibiotic producing microorganism. Transformation of C. acremonium 394-4 caused an increase in the amount of antibiotic cephalosporin C excreted by the organism. Cephalosporins are beta-lactam compounds that are structurally and pharmacoligically related to penicillins. Cephalosporins resist hydrolysis by enzymes referred to as penecillinases, which are secreted by a number of bacteria. They are now one of the most widely prescribed antibiotics and are very effective for the treatment of hospital-acquired infections.

Actinomycetes are aerobic spore forming bacteria that originate from soil. A large number of antibiotics are produced by actinomycetes and in particular Streptomyces. They resemble a fungal mycelium in form, but have thinner filaments. These filaments are formed when cells divide to form long chains of up to 50 cells. Actinomyces griseus was first isolated from soil in the Andes, this bacterium produced a substance that killed many bacteria unaffected by penicillin, including Tuburculosis bacillus. The antibiotic was named streptomycin. However tubercle bacilli soon became resistant to streptomycin and it has since been replaced by para-amino-salicylic acid (PAS). Stretomycetes are still very important bacterial producers of antibiotics and cytostatics. Due to the emerging resistance of bacteria to common antibiotics, new technologies such as combitatorial biosynthesis are being used for the production of novel metabolites using streptomycetes. This technology involves the use of a combination of genes from different biosynthetic pathways to produce modified metabolites.

Ordinarily Actinomycetes use the EMP pathway to metabolise glucose because this pathway is a more efficient one than the ED pathway. The secondary metabolites of the fungi including Drechslera, Trichoderma, Aspergillus and Curvularia have the ability to produce green dyes / anthraquinones.. These dyes are from natural sources and do not cause the pollution to the environment associated with chemical dyes.

So in nutshell Industrially important primary microorganisms are continually being improved to optimize product yield and substrate utilization in order to minimize the cost of production. Primary products of microbial metabolism have made a significant contribution to the food and beverage industries. Primary metabolites have been used to produce petroleum derived products as well as ethanol for liquid fuels (gasohol). Considering the current trends in oil prices, microorganisms that have the ability to produce such products will no doubt be exploited to their full potential. In the not too distant future biomass energy could become a major contributor to the Earth’s energy requirements as petroleum resources run out. The introduction of antibiotics revolutionised the treatment of infectious disease in humans. Antibiotics are used in large quantities in animal farming to prevent infection as well as to treat diseases. Smaller doses are added to animal feed to promote growth. Fruits and vegetables are also treated for bacterial infections using antibiotics such as streptomycin and oxytetracycline. Owing to this widespread use, antibiotics have been found in liquid waste at animal feedlots and have spread into many surface and groundwater supplies. Residues of antibiotics have also been detected in sewage treatment plants and raw water resources in many European countries. The prescence of antibiotics has upset the delicate balance of microorganisms in the environment by depletion of microorganisms susceptible to antibiotics and providing favourable environments for the proliferation of resistant strains. Three EU projects were undertaken in 2003 to assess the presence and effects of antibiotics in the aquatic environment and in soils: the ERAVMIS, PEPHARMAWATER and POSEIDON projects. These projects also propose solutions to this problem, such as the removal of antibiotics from wastewater by ozonation and sunlight. Bioresearch Italia began a project to isolate previously unexploited microorganisms from actinomycetes and uncommon filamentous fungi in 2002. This project may provide some insight into methods of combating the increasing number of antibiotic resistant strains of bacteria.

References:

http://www.msu.edu/course/mmg/301/lec

Krishna, C., 19xx, Solid state fermentation systems - an overview, Journal of

Applied Microbiology, Vol. 25 Issues 1-2, pp1-30

Learry, E; Keegan, J; primary versus secondary metabolites

PENICILLIN PRODUCTION

2011-12-06T19:40:00.001-08:00

PENICILLIN PRODUCTION:

Penicillin was the first naturally occurring antibiotic discovered. It is obtained in a number of forms from Penicillium moulds. Penicillin is not a single compound but a group of closely related compounds, all with the same basic ring-like structure (a β-lactam) derived from two amino acids (valine and cysteine) via a tripeptide intermediate. The third amino acid of this tripeptide is replaced by an acyl group (R) and the nature of this acyl group produces specific properties on different types of penicillin.

There are two different types of penicillin.

Biosynthetic penicillin is natural penicillin that is harvested from the mould itself through fermentation.

Semi-synthetic penicillin includes semi synthetic derivatives of penicillin - like Ampicillin, Penicillin V, Carbenicillin, Oxacillin, Methicillin, etc. These compounds consist of the basic Penicillin structure, but have been purposefully modified chemically by removing the acyl group to leave 6-aminopenicillanic acid and then adding acyl groups that produce new properties.

These modern semi-synthetic penicillins have various specific properties such as resistance to stomach acids so that they can be taken orally, a degree of resistance to penicillinase (or β-lactamase) (a penicillin-destroying enzyme produced by some bacteria) and an extended range of activity against some Gram-negative bacteria. Penicillin G is the most widely used form and the same one we get in a hypodermic form.

PENICILLIN G

Penicillin G is not stable in the presence of acid (acid-labile). Since our stomach has a lot of hydrochloric acid in it (pH2.0), if we were to ingest penicillin G, the compound would be destroyed in our stomach before it could be absorbed into the bloodstream, and would therefore not be any good to us as a treatment for infection somewhere in our body. It is for this reason that penicillin G must be taken by intramuscular injection - to get the compound in our bloodstream, which is not acidic at all. Many of the semi-synthetic penicillins can be taken orally.

Penicillium chrysogenum that produce antibiotics, enzymes or other secondary metabolites frequently require precursors like purine/pyrimidine bases or organic acids to produce said metabolites. Primary metabolism is the metabolism of energy production for the cell and for its own biosynthesis. Typically, in aerobic organisms (Penicillium chrysogenum) it involves the conversion of sugars such as glucose to pyruvic acid2 and the production of energy via the TCA cycle. Secondary metabolism regards the production of metabolites that are not used in energy production for example penicillin from Penicillium chrysogenum. In this case the metabolite is being utilized as a defence mechanism against other microorganisms in the environment. In essence Penicillium chrysogenum can kill off the competition to allow itself to propagate efficiently. It should be noted that these secondary metabolites are only produced in times of stress when resources are low and the organism must produce these compounds to kill off its competitors to allow it to survive.

MEDIA FORMULATION:

Lactose: 1%

Calcium Carbonate: 1%

Cornsteep Liquor: 8.5%

Glucose: 1%

Phenyl acetic acid: 0.5g

Sodium hydrogen phosphate: 0.4%

Antifoaming Agent: Vegetable oil

FERMENTATION

To begin the fermentation process, a number of these spores will be introduced into a small (normally 250-500ml) conical flask where it will be incubated for several days. At this stage, explosive growth is the most desired parameter and as such the medium in the flask will contain high amounts of easily utilisable carbon and nitrogen sources, such as starch and corn-steep liquor. At this stage, the spores will begin to revive and form vegetative cells. Temperature is normally maintained at 23-280C and pH at ~6.5, although there may be some changes made to facilitate optimum growth. The flask will often have baffles in it and be on a shaking apparatus to improve oxygen diffusion in the flask.

Once the overall conditions for growth have been established and there is a viable vegetative culture active inside the flask, it will be transferred to a 1 or 2 litre bench-top reactor. This reactor will be fitted with a number of instruments to allow the culture to be better observed than it was in the shake flask. Typical parameters observed include pH, temperature, and stirrer speed and dissolved oxygen concentration. This allows tweaking of the process to occur and difficulties to be examined. For example, there may not be enough oxygen getting to the culture and hence it will be oxygen starved. At this point, the cells should be showing filamentous morphology, as this is preferred for penicillin production. As before, cell growth is priority at this stage. At this stage, growth will continue as before, however, there are often sudden changes or loss in performance. This can be due to changes in the morphology of the culture (Penicillium chrysogenum is a filamentous fungi and hence pseudoplastic) that may or may not be correctable.

At this stage the medium being added to the reactor will change. Carbon and nitrogen will be added sparingly alongside precursor molecules for penicillin fed-batch style. Another note is that the presence of penicillin in the reactor is itself inhibitory to the production of penicillin. Therefore, we must have an efficient method for the removal of this product and to maintain constant volume in the reactor. Other systems, such as cooling water supply, must also be considered. If all goes well we should have penicillin ready for downstream processing. From here it can be refined and packaged for marketing and distribution to a global market.

References:

1. Hare, T; White, L / penicillin production

2.http://nobelprize.org/medicine/educational/penicillin/readmore.html

PHOTOSYSTEM I & II; RED DROP EFFECT

2011-12-05T08:14:00.001-08:00

RED DROP EFFECT:

Wavelengths beyond 700nm are apparently of insufficient energy to drive any part of photosynthesis. So a huge drop in efficiency has been noticed at 700nm. This phenomenon is called as RED DROP EFFECT. In other words there is a sharp decrease in quantum yield at wavelengths greater than 680nm. This decrease in quantum yield takes place in the red part of the spectrum. The number of oxygen molecules released per light quanta absorbed is called as quantum yield of photosynthesis. This effect was first of all noticed by Robert Emerson of Illinois University. Later on Emerson and his group observed that if chlorella plants are given the inefficient far red light and red light of shorter wavelengths in alternate fashion, the quantum yields were greater than could be expected from adding the rates found when either colour was provided alone. This synergistic effect or enhancement is known as EEE or Emerson Enhancement Effect. This was the first good evidence that there are two photo systems; one absorbs far red light and other red light and both of them must operate to drive photosynthesis most effectively.

PHOTOSYSTEMS I & II: COMPOSITION, LOCATION AND FUNCTIONS IN THYLAKOIDS:

The two photo systems can be separated from thylakoids by PAGE.

Major green bands shows PS I which contains chl a, small amounts of chl b , some beta carotenes. One of the chl a molecule is made somehow special by its chemical environment so that it absorbs light near 700nm so it is called as P700 which is the reaction centre for PS I and to which surrounding carotenes and chlorophyll molecules in that photosystem transfer their energy. At least 2 iron containing proteins similar to ferredoxin are also present in which each of four iron atoms in each protein is bound to 2 sulfur atoms; these are called as Fe-S proteins. The Fe-S proteins are primary electron acceptors for PS I. Only one of the 4 iron atoms present can accept electrons and as a result Fe ³⁺ will be reduced to Fe^2+.Subsequently Fe²⁺ is reoxidised to Fe³⁺during electron transport pathway.

PS II also contains chl a, chl b . the eraction centre is P 680. The primary electron acceptor is colorless chl a that lacks Mg^2+. This molecule is called as pheophytin; abbreviated as pheo. Associated with pheo is quinone which is abbreviated as Q because of its ability to quench fluorescence of P680 by accepting its excited electron. PS II also contains one or more proteins containing bound manganese. It is believed that 4 Mn²⁺are bound to one or more proteins and one cl^- bridges two Mn²⁺ together.

Apart from two photosystems 2 LHCs (light harvesting complexes) are also present; one of which functions with PS I and other functions with PS II. Their function is to harvest light energy by absorbing it and transferring it to proper photosystem, where it eventually reaches to P680 pr P700.

To solve the problem of cooperation between 2 Photosystems because of their distant locations two mobile electron carriers are also present. These are PQ (plastoquinone) and PC (plastocyanin). PC is copper containing pigment which is bound loosely to inside of thylakoid membranes next to channel. When its copper becomes reduced from Cu²⁺to Cu⁺¹by PS II, it can move along the membrane carrying an electron to PS I where it is reoxidised to Cu²⁺ form. it then shuttles back to PS II and picks up still another electron. Another carrier system is a group of Quinones called PQs that moves laterally and vertically within the fluid membranes. PQs carry 2 electrons and two protons from PS II to PS I.

Cooperation of 2 PSs also require more electron transport systems. Another complex of proteins are cyt b₆_, cyt f and cyt _b3 and Fe-S protein called ferredoxin. Fd transfers electrons from other Fe-S proteins of PS I directly to NADP+ completing the electron transport process.

A final component of thylakoids essential for the photophosphorylation is ATPase or CF complex. This complex either hydrolyzes ATP to ADP and Pi. Or synthesize ATP from Pi and ADP by photophosphorylation. So ATP synthesis is strongly favoured by electron transport and electron transport is favoured by photophosphorylation, so CF couples the two processes together.

CITRIC ACID PRODUCTION

2011-12-05T03:59:00.001-08:00

CITRIC ACID PRODUCTION

The first ever commercial production of citric acid was launched in UK by Sturage Company by JOHN & EDMUND; 1826

In 1880; Citric acid was first synthesised from glycerol

In 1893; Wehmer observed occurrence of citric acid as a microbial product by using penicillium.

In 1922; Millard recorded accumulation of citric Acid In culture of Aspergillus niger under condition of nutrition deficiency.

In 1923; Pfizer began fermentation based process in USA

PRODUCTION

1. Fermentation: A. niger is the choice for production of citric acid for several decades. Large number of other microbes such as P.luteum, P.cirinum, pichia spp. Have also been used. Fermentation can be carried out by any of following processes:

a) KOJI PROCESS (solid state fermentation): it’s a Japanese process in which special strains of A.niger are used with solid substrate such as sweet potato starch. Mold is used to which wheat bran was substituted. The pH of bran was adjusted between 4–5 and additional moisture is picked up during steaming so as to get water content of mash around 70 – 80%. After cooling the bran to 30 – 60^oCthe mass is inoculated with KOJI which was made by a special strain of A.niger. Since bran contains starch which on saccharification produces citric acid by amylase of A.niger. Bran after inoculation is spread in trays to a depth of 3 – 5 cm and kept for incubation at 25-30^oC. After 5 – 8 days koji is harvested and citric acid is extracted.

b) Liquid Surface Culture Process: in this case aluminium or stainless steel shallow pans or trays are used. Sterilized medium contains molasses and salts. Fermentation is usually carried out by blowing spores of A.niger over the surface of the solution for 5-6days. Spore germination occurs within 24 hours and a white mycelium grows over the surface of the solution. After 8-10days of inoculation liquid can be drained off and citric acid can be extracted from the mycelia mat.

c) Submerged Culture Process: this method is quite economical. In this case A. japonicus (black mold) is slowly bubbled in a stream of air through a culture solution. Since organism shows subsurface growth and produces Citric acid in culture solution the yields are inferior in comparison to liquid surface culture fermentation.

Referencing a Web Page

2011-12-04T19:19:00.001-08:00

Referencing a web page

When referencing something you have found on the web you need to distinguish what you are referring to as the internet is made up of a vast range of material from journal articles to personal and organisational websites. Below is a list of information you can include:

Author/Editor or Organisation, Year the site was published or last updated, Title of work - main title and subtitle (screen heading/sub-heading), Online address or location within database - full address (URL or DOI), Date you looked at the information, the access date.

You can also include other identifying features such as a page or screen reference, paragraph or line number or perhaps a labelled section or part of a table or graph.

Type of medium - for example online database, online bulletin board.

Publisher and place of publication - for example documents on portable databases, which organisation has prepared the materials and where they are located.

Name of database.

Organisational website: following is the example for referencing a website:

National Trust (2011) Planning for the people. Available at: http://www.nationaltrust.org.uk/main/w-chl/wcountryside_environment/w-planning-landing.htm (Accessed: 20 September 2011).

Referencing BOOKS (print/online)HARVARD STYLE

2011-12-04T18:37:00.001-08:00

This article is for those students who struggle for referencing; i have assembled various types of referencing in different posts under different headings. This is Harvard style of referencing. I'm sure you want to learn it because you don't want to be the victim of plagiarism.

List of references

At the end of your essay, place a list of the references you have cited in the text. Arrange this in alphabetical order of authors' surnames, and chronologically (earliest publication date first) for each author, where more than one work by that author is cited. The author's surname is placed first, followed by initials or first name, and then the year of publication is given.

Books (print and online)

Type	Examples
One author	Cole, GHA 1991, Thermal power cycles, Edward Arnold, London. Series titles and edition statements (for editions other than the first) should be included. Goldsworthy, J 2010, Parliamentary sovereignty: contemporary debates, Cambridge studies in constitutional law, Cambridge University Press, Cambridge. Abbott, HP 2008, The Cambridge introduction to narrative, 2nd edn, Cambridge University Press, Cambridge.
Two or more authors	List all authors in the list of references. See the second part of this guide for how to cite in-text. Douglas, M & Watson, C 1984, Networking, Macmillan, London. Flexer, RW, Baer, RM, Luft, P & Simmons, TJ 2008, Transition planning for secondary students with disabilities, 3rd edn, Pearson, Upper Saddle River, New Jersey.
Two or more books in one year by the same author	List in alphabetical order by title. King, P 1984a, Power in Australia, UQP, St. Lucia. ------- 1984b, Solar power, Macmillan, Melbourne.
Edited books	If the role of an editor (or compiler, reviser or translator) is of primary importance, list the work under those names. Use abbreviations such as ed., eds, trans., rev., comp. and comps. Long, PE (ed.) 1991, A collection of current views on nuclear safety, Penguin, Harmondsworth. Ahdar, R & Aroney, N (eds) 2010, Shari'a in the West, Oxford University Press, Oxford.
Chapters in edited books	Callaghan, J 2010, 'Singing teaching as a profession', in S Harrison (ed.), Perspectives on teaching singing: Australian vocal pedagogues sing their stories, Australian Academic Press, Bowen Hills, Queensland. Shachar, A 2010, 'State, religion, and the family: the new dilemmas of multicultural accommodation', in R Ahdar & N Aroney (eds), Shari'a in the West, Oxford Unversity Press, Oxford.
Editions	The edition (if other than the first edition) is included after the main title. Morton, JS 1984, Wind power: an overview, 2nd edn, Melbourne University Press, Melbourne.
Part of a series	The series title is included after the main title. Muller, R & Turner, JR 2010, Project-oriented leadership, Advances in project management, Gower, Farnham, England. Editions go after the series title. Corrigan, T 2010, A short guide to writing about film, The short guide series from Pearson Longman, 7th edn, Longman, New York.
Anonymous (no author or editor given)	Start with the title. The eliciting of frank answers 1955, Engineering Publications, Florida.
Conference paper	Trump, A 1986, 'Power play', Proceedings of the third annual conference, International Society of Power Engineers, Houston, Texas, pp. 40-51.
Page numbers	Occasionally, it may be necessary to cite page numbers for books. If so, present the numbers as the final item of the citation as in the example above (e.g. p. 10, pp. 19-25, pp. 21-6, pp. 21, 31-5).
Acknowledging editors, compilers, revisers or translators	If the author's role remains of primary importance, editors, compilers, revisers or translators can also be acknowledged. Use abbreviations such as ed., eds, trans., rev., comp. and comps. Tolstoy, L 1930, What is art? and essays on art, trans. A Maude, Oxford University Press, London. Mayakovsky, V 1942, Mayakovsky and his poetry, comp. H Marshall, Pilot Press, London.
Corporate authors	The jurisdiction is not usually given for government agencies but is indicated by the place of publication. Department of Energy 1980, Projections of energy needs, HMSO, London. Office of the Aboriginal Land Commissioner 2001, Urapunga land claim no. 159, Parliamentary paper, Aboriginal and Torres Strait Islander Commission, Canberra. Xerox Corporation 1988, Xerox publishing standards: a manual of style and design, Watson-Guptil, New York. Parent bodies precede subdivisions. World Association of Veterinary Anatomists. International Committee on Avian Anatomical Nomenclature 1979, Nomina anatomica avium: an annotated anatomical dictionary of birds, Academic Press, London.
Online books	Author Year (of creation or last revision), Title, edition/version (if applicable), name and place of the sponsor of the source (publisher, place), viewed Day Month Year,<URL either full location details or just the main site details>. McClain, M & Roth JD 1999, Schaum's quick guide to writing great essays, McGraw-Hill, New York, viewed 17 January 2005, <http://ezproxy.usq.edu.au/login?url=http://site.ebrary.com/lib/unisouthernqld/Doc?id=5002145>. Fitzgerald, FS 1920, This side of paradise, Scribner, New York, viewed 18 January 2005, <http://www.bartleby.com/115/>.
Chapters in an online books	Author Year (of creation or last revision), 'Chapter title', in book editor(s) (ed.), Book title, name and place of the sponsor of the source (publisher, place), viewed Day Month Year, <URL either full location details or just the main site details>. Gould, SJ 2000, 'More things in Heaven and Earth', in H Rose & S Rose (eds), Alas, poor Darwin: arguments against evolutionary psychology, Harmony Books, NewYork, viewed 17 January 2005, <http://ezproxy.usq.edu.au/login?url=http://site.ebrary.com/lib/unisouthernqld/Doc?id=10015543>.

Time for fun

2011-12-02T17:57:00.001-08:00

And this one is for all those who really think that metabolism is not for them! they find it so hard to remember those complex pathways and cycles!!!

but i am sure you would love this Kreb's Cycle!!!!
;)

L-Lysine Production

2011-12-02T06:34:00.001-08:00

L-Lysine Fermentation

Out of 20 naturally occurring amino acids, L- lysine is one of 9 essential amino acids and commercially important amino acids. It is mainly used as feed additive in the animal feed industry; mixed with various common livestock such as cereals which do not contain sufficient levels of L-Lysine for the livestock’ nutritional requirements, in especially monogastric animals like broilers, poultry and swine and as a supplement for humans and improving the feed quality by increasing absorption of other amino acids.

L-Lysine can be produced by chemical or biochemical method; whichever is more economic. Gram+ve cyanobacteria strains like Corynebacterium glutamicum, Brevibacterium flavum are used for industrial production.

Fermentation Medium:

Apart from physical parameters like pH, Agitation and aeration rate and temperature; media composition is very important factor.

The seed culture to be prepared includes:

Glucose: 20g

Peptone: 10g

Meat extract: 5g

Sodium chloride: 2.5g in 1 litre of tap water

Seed culture obtained is reinoculated for 2^nd seed culture in media containing:

Molasses: 200g

Soy protein hydrolysate 18g in 1L tap H₂O

Above culture is reinoculated with B.flavum

Acetate is used as C source

After obtaining first and second media production media is used which includes:

Cornsteep liquor

Ammonium sulphate

Glycerol

CaCO₃

Incubation for 72 hours at 28 degrees

Recovery:

Fraction of lysine fermentation broth is obtained by any suitable, Methods such as Ultrafiltration or Centrifugation. In order to overcome difficulties of high viscosity in culture broth; filterability can be improved by adding a mineral acid like conc. H₂SO₄ and then heat the culture broth at 100degrees for at least 5 minutes. The resulting product is L lysine.