Wednesday, 14 December 2011
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 CO2 for 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.
Tuesday, 6 December 2011
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.
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).
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.
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 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 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.
Calcium Carbonate: 1%
Cornsteep Liquor: 8.5%
Phenyl acetic acid: 0.5g
Sodium hydrogen phosphate: 0.4%
Antifoaming Agent: Vegetable oil
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.
1. Hare, T; White, L / penicillin production
Monday, 5 December 2011
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 Fe2+. 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 Mg2+. 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
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
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 – 60oC the 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 25-30oC. 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.
Sunday, 4 December 2011
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).
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)
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.
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.
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.
Trump, A 1986, 'Power play', Proceedings of the third annual conference, International Society of Power Engineers, Houston, Texas, pp. 40-51.
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.
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.
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,
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>.
Friday, 2 December 2011
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.
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:
Meat extract: 5g
Sodium chloride: 2.5g in 1 litre of tap water
Seed culture obtained is reinoculated for 2nd seed culture in media containing:
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:
Incubation for 72 hours at 28 degrees
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.
Apparently i do have a BLOG which i think is waiting for me to write !! But feeling so exhausted with this cold and fever. So i apologize to my students with whom i have promised for notes. Sorry Guys i will be back soon..
Wish you luck for the forthcoming exams.
And do let me know how did you find today's 4 Lectures in a row!!! I am sure you must be saturated enough!!
Have a Happy Learning.
And while you wait for my next post listen to this (a motivational song)
Hope you'll like it!
See you Soon.
Wish you luck for the forthcoming exams.
And do let me know how did you find today's 4 Lectures in a row!!! I am sure you must be saturated enough!!
Have a Happy Learning.
And while you wait for my next post listen to this (a motivational song)
Hope you'll like it!
See you Soon.
Tuesday, 22 November 2011
The Michaelis Menton Equation: a generalized theory of enzyme action was formulated by Leonor Michaelis and Maud Menton in 1913. The derivation starts with a basic step involving formation and breakdown of the ES complex.
The overall reaction is:
E + S ES E + P
the initial velocity V0 can be determined by the breakdown of ES complex into product which is give by:
V0 = k2 [ES] Eq No. 1
Since it is not easy to measure [ES] experimentally we should figure out an alternative expression of [ES]. So , we will consider [Et ], that denotes for total enzyme concentration.
Free or unbound enzyme can be represented by:
[Et] – [ES]
The rate of formation and breakdown of ES can be determined by:
Rate of ES formation = k1 ([Et] – [ES])[S]
Rate of ES breakdown = k-1 [ES] + k2 [ES]
At the steady state rate of [ES] formation will be equal to ES breakdown so above equation can be written as:
k1 ([Et] – [ES])[S] = k-1 [ES] + k2 [ES]
To solve the above equation multiply the left side and simplify the right side:
k1[Et][S] - k1[ES][S] = (k-1 + k2)[ES]
add the term k1[ES][S] to both sides of the equation:
k1[Et][S] = (k1[S] + k-1 + k2)[ES]
and then solve the equation for [ES]:
[ES] = [Et][S]
[S] + (k2 + k-1)/k1
The term (k2 + k-1)/k1 is defined as Michaelis constant Km
Substitute km into above equation:
[ES] = [Et][S]
[S] + Km
Now V0 can be expressed in terms of [ES] by substituting above equation into equation no.1:
[S] + Km
Since maximum velocity occurs when enzyme is saturated with [ES] = [Et] so Vmax can be defined as k2 [Et] so substitute the value of V0 into above equation:
V0 = Vmax [S]
[S] + Km
The above equation is called as Michaelis Menton equation.
A numerical relationship exists in the Michaelis menton equation when V0 is exactly one half of Vmax . then:
Vmax / 2 = Vmax [S]
[S] + Km
Divide above equation by Vmax we get:
½ = [S] / Km + [S]
Solving for Km we get Km + [S] = 2 [S],
Or km = [S] , when V0 = ½ Vmax
Transformation of Michaelis Menton equation: Double Reciprocal plot
V0 = Vmax [S]
[S] + Km
Take the reciprocal of above equation:
1/V0 = Km + [S] / Vmax [S]
Separate the components of numerator on the R.H.S of the equation and after simplification we get:
1/V0 = Km + [S]
This equation is known as double reciprocal plot or Lineweaver Burk equation.