Strain improvemnet of a fungus producing chitinase by a chemical mutagen

Microbial chitinases are commercially exploited for their biocontrol properties and generation of useful products from chitinous waste. Availability of highly active chitinolytic enzymes is a major problem. The present study was carried out to improve chitinase production by Aspergillus terreus using a chemical mutagen, ethidium bromide. The organism was cultivated on lactose- yeast extract medium. The production medium consisting of chitin- yeast extract medium was seeded at 10% level. The wild strains were exposed to ethidium bromide in the concentration range 1.5- 6.0 μg/ml. Generally all the mutated strains showed an improved chitinase yield compared to the control. Highest yield was observed with the strain exposed to 6 μg/ml of ethidium bromide. The yield was 25.03 % higher compared to the wild strain. The mutated strain was slimy in nature. Protein content of the mutated strain decreased by 11%. Ethidium bromide at a concentration of 1.5 μg/ml was considered better at which the strain was stable with increase of 21.80 % in enzyme activity and 4.41% increase in protein content. Increased enzyme yield with decreased non-specific protein could be useful in producing cost effective enzyme.