used in treating wounded American soldiers in world war II. Fleming, Chain and Florey were awarded Nobel Prize in 1945. Waksman
and Woodruff isolated actinomycin in 1941 and streptothricin in 1942.
Waksman and Albert (1943) and Waksman (1944) discovered streptomycin. Burkholder (1947) isolated chloromycetin. Over
7000 antibiotics are known.
Table: Some common antibiotics, their source and action.
Antibiotics Source Action
Chloramphenicol S. venezuelae Typhoid, whooping cough
Erythromycin S. erythreus Diphtheria
Chloromycetin S. lavendulae Pneumonia
Streptomycin S. griseus Meningitis, Pneumonia, TB
Bacitracin Bacillus licheniformis Syphilis, Lymphonemaproduction of antibiotics
Various steps involved in the production of an antibiotic have been summarised in the table given below.
bioactive molecules
Cyclosporin - A is an important bioactive chemical produced by the fungus Trichoderma polysporum. It is an 11-membered cyclic
oligopeptide. This chemical is used as an immunosuppressive agent in organ transplantation.
Statin is produced by yeast Monascus purpureus. It is used as blood cholesterol lowering agent by acting as a competitive inhibitor
of enzyme for cholesterol synthesis. Some microbes are used to obtain organic acids, enzymes etc.
organic acids
Microbes are also used for commercial and industrial production of certain organic acids. The first organic acid produced through
microbial fermentation was lactic acid (Scheele, 1789). Some other common organic acids produced through microbial activity are
acetic acid, citric acid and butyric acid.
There are mainly two steps in acetic acid or vinegar production. In the first stage yeast converts sugar into ethanol anaerobically
while in the second step ethanol is oxidised to acetic acid aerobically by Acetobacter aceti. This process is called acetification. This
organic acid is employed in pharmaceuticals, colouring agents, insecticides, plastics, etc.
Citric acid is obtained through the fermentation carried out by Aspergillus niger and Mucor species on sugary syrups. Yeast can also
be employed, provided its nutrient medium is made deficient of iron and manganese. Citric acid is employed in dyeing, engraving,
medicines, inks, flavouring and preservation of food and candies.
Lactic acid fermentation is carried out by both bacteria (e.g., Streptococcus lactis, Lactobacillus species) and fungi (e.g., Rhizopus).
Clostridium acetobutylicum is the bacteria that is used for production of butyric acid.
enzymes
Enzymes are proteinaceous substances of biological origin which are capable of catalysing biochemical reactions without themselves
undergoing any change.
Streptokinase (Tissue Plasminogen Activator or TPA) is an enzyme obtained from the cultures of some haemolytic streptococci.
It has fibrinolytic effect. Therefore, it helps in clearing blood clots inside the blood vessels through dissolution of intravascular fibrin.
Pectinases are obtained commercially from Byssochlamys fulva. Along with proteases, they are used in clearing of fruit juices. Other
uses are in retting of fibres and preparation of green coffee.
Lipases are lipid dissolving enzymes that are obtained from Candida lipolytica and Geotrichum candidum. Lipases are added in
detergents for removing oily stains from laundry. They are also used in flavouring cheese.