bioactive molecules Microbes are not only used for commercial and industrial production of alcohol, but also used for production of chemicals like organic acids and enzymes. Examples of organic acid producers are Aspergillus niger for citric acid , Acetobacter aceti for acetic acid , Rhizopus oryzae for fumaric acid , Clostridium butyricum for butyric acid and Lactobacillus for lactic acid . Yeast ( Saccharomyces cerevisiae ) and bacteria are used for commercial production of enzymes. Lipases are used in detergent formulations and are used for removing oily stains from the laundry.
Bottled juices are clarified by the use of pectinase, protease and cellulase . Rennet can also be used to separate milk into solid curds for cheese making. Streptokinase produced by the bacterium Streptococcus and genetically engineered Streptococci are used as “ clot buster ” for Biodiesel is a fuel made from vegetable oils, fats or greases. Biodiesel fuel can be used in diesel engines without altering the engine.
Pure biodiesel is non-toxic, biodegradable and produces lower level of air pollutants than petroleum-based diesel fuel. The Government of India approved the National Policy on Biofuels in December and identified Jatropha curcas as the most suitable oilseed for biodiesel production. Pongamia species is also a suitable choice for production of biodiesel. XII Std Zoology Chapter XII Std Zoology Chapter Microbes in Human Welfare Biogas is devoid of smell and burns with a blue flame without smoke.
The Methanogens are also present in anaerobic sludge and rumen of cattle. In rumen, these bacteria help in the breakdown of cellulose. The excreta of cattle called dung is commonly called “ Gobar ”. Gobar gas is generated by the anaerobic decomposition of cattle dung.
It consists of methane, CO with some hydrogen, nitrogen and other gases in trace amounts. Fig. . Biogas Unit In a biogas plant, anaerobic digestion is carried out in an air tight cylindrical tank known as digester (Fig.
. ) . It is made up of concrete bricks and cement or steel. Bio-wastes are collected and slurry of dung is fed into this digester.
It has a side opening into which organic materials for digestion are incorporated for microbial activity. Anaerobic digestion is accomplished in three stages: solubilisation, acidogenesis and methanogenisis. The outlet is connected to a pipe to supply biogas. The slurry is drained through another outlet and is used as fertilizer.
Biogas is used for cooking and lighting. The technology of biogas production was developed in India mainly due to the efforts of Indian Agricultural Research Institute (IARI) and Khadi and Village Industries Commission (KVIC).