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The below mentioned article provides a note on microbial biotechnology.
Biotechnology is the application of living organisms and their products in industrial processes on large scale. Microbial biotechnology is that aspect of biotechnology which involves the use of microorganisms or their products.
Microbial biotechnology is sometimes also referred to as industrial microbiology which is an old field that has been given new dimensions because of the discoveries made in the field of genetic engineering in vitro manipulation of DNA molecules to generate new combinations of genes or sequences, to place the gene under the control of different regulatory systems, to introduce a specific mutation in a molecule, etc.
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Industrial microbiology came into existence initially by establishment of alcoholic fermentation processes to produce wine and beer. Thereafter, came the microbial production of antibiotics, and food additives such as amino acids, enzymes, butanol and citric acid.
Genetic engineering has enabled us to use microorganisms for production of new substances which the microorganisms could not have produced normally, such as the production of hormone insulin a pancreatic hormone which stimulates the transportation of glucose into cells. The production of insulin by bacterium has been possible due to genetic engineering techniques of inserting human insulin gene into bacterium.
Microbial biotechnology can be divided under two subheadings:
(1) Traditional microbial technology which is the large scale manufacture of products which are normally produced by microorganisms.
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(2) Microbial technology with genetically engineered microorganisms in which new genes have been inserted.
Industrial Microorganisms:
Industrial microorganisms are those microorganisms which have been selected carefully to make one or more specific products. Industrial microorganisms are selected for their metabolic activities which are capable of specific products and give high yield of particular metabolites.
To achieve the desired objectives of high metabolic specialization the industrial strains are genetically modified by mutation or recombination using techniques of genetic engineering. The minor metabolic pathways are either brought down or eliminated. Though the industrial strains may grow well under highly specialized artificial conditions of the fermenter they may show poor growth characteristics in natural conditions of competitive environments.
Source of Industrial Strains:
The initial and ultimate source of industrial strains has no doubt been nature but through the experience of years of large scale microbial processes perfection has been achieved for greater yield. The strains so developed have been deposited in culture collections. To get a new industrial process patented, the applicant is required to deposit a strain capable of carrying on the process, to a recognized culture collection.
Although most industrial companies would be reluctant to deposit their best cultures with any recognized culture collection, yet these collections serve as a ready source of cultures: A very big list of culture collections is given in the “World Directory of Collection of Microorganisms” (1982), updated by V.F. Mc Gowan and V.B.D. Skerman.
Some of the general culture collections with their abbreviation, full name and locations are given below:
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AMRC (FAO-WHO International Reference Centre for Animal Mycoplasma) Institute of Medical Microbiology, University of Aarhas, Denmark.
ATCC (American Type Culture Collection) 12301.
Parklawan Drive, Rockvilla, Maryland 20852, USA.
CBS (Central Bureau Voor Schimmelcultures) Oousterstraat 1, Baarn, The Netherlands.
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CCEB (Culture Collection of Entomophagous Bacteria) Institute of Entomology, Czechslovak Academy of Sciences, Femingovo N2, Prague 6, Czechoslovakia.
CDDA (Canadian Department of Agriculture) Ottawa, Canada.
CIP (Collection of Institute Pasteur) Rue due Dr Roux, Paris 15, and France.
CMI (Commonwealth Mycological Institute presently known as International Mycological Institute) Kew, UK.
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DSM (Deutsche Samn—dung von Microorganismen) Grisebachstrasse 8, Gottingen, Federal Republic of Germany.
FAT (Faculty of Agriculture, Tokyo University) Tokyo, Japan.
IAM (Institute of Applied Microbiology) University of Tokyo, Bunkyo-ku, Tokyo, Japan.
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IFO (Institute of Fermentation) 4-54 Jusonishinocho, Osaka Japan.
IMI (International Mycological Institute) Bakeham Lane, Egham, Surrey TW 209 TY, UK.
IMY (Institute of Microbiology & Virology) Academy of Sciences of the Ukranian S.S.R., Kiev.
NCIB (National Collection of Industrial Bacteria) Aberdeen, Scotland.
NCTC (National Collection of Type Cultures), London, U.K.
NRRL (Northern Regional Research Laboratory) Peoria, IL USA.
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UQM (Culture Collection, Department of Microbiology, University of Queensland), Herston, Brisbane 4006, Australia.
UWO (University of Western Ontario Culture Collection, Department of Plant Sciences), Ontario N6A 587, Canada.
Maintenance and preservation of cultures is also very essential for getting cultures from the culture collections.
Strain Improvement:
Microorganisms from original sources are highly modified in the laboratory. The modification is done to achieve a target of higher yield. One of the interesting examples of the progressive improvement is the antibiotic penicillin produced by the fungus Penicillium chrysogenum. The production of penicillin on industrial scale was for the first time 1 to 10 pg/ml.
However, the programmes of strain development accompanied by changes in medium and the growth conditions after hard work of many years, increased the yield of antibiotic penicillin to about 50,000 pg/ml. Thus, almost 50,000 times increase was possible by mutation and selection without involving genetic engineering techniques. The addition of new genetic engineering techniques has brightened the chances for yet greater yield.
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Requisites for an Industrial Microorganism:
Not all but only a few selected microorganisms are suitable for application in industrial production. An industrial microorganism must grow readily in large-scale manufacturing equipment. No doubt an industrial microorganism’s first requisite is to manufacture the product of interest but it must also grow rapidly and on relatively cheap culture media.
An industrial microorganism should have the possibility of undergoing manipulations genetically for its strain improvement. An industrial microorganism should neither be pathogenic nor it should produce any toxic products which may be harmful to humans, animals or plants.
