Enhancement of protease production by Bacillus sp. and Micrococcus varians induced by UV-mutagenesis

Microbial proteases contribute nearly 40% of the total worldwide enzyme market. Hence, with the view of this significance, the main objective of the present study was to enhance protease production of two bacterial strains, Bcillus sp. and Micrococcus varians using UV mutagenesis. Induction of mutation in both strains was carried out at different exposure times: 0, 3, 6, 9, 12, 15, 18 and 21 min at a distance of 10 between UV source and treated bacteria.Two best protease producer mutants for the two bacterial strains (UV-9 for Bcillus sp.and UV-18 forMicrococcus varians) were selected based on the clearance zone diameter of mutant colonies on 1% skimmed milk agar plates. UV-9 mutant showed 1.4 fold higher protease activity than the wild type in solid and liquid medium. However UV-18 mutant was found to produce 2.5 fold increases over the wild type on agar plates and 2.1 fold enhancement in liquid-medium assay.The two mutants were very effective in feather keratin-degrading in less than two days, UV- 18 was more efficient than UV-9.