P. PALLAVI, S. JEEVAN CHANDRA AND S. RAM REDDY
Abstract
Improvement of microbial strains for over production of industrial products has been the hallmark of all commercial fermentation processes. In our studies, based on16S rDNA nucleotide sequence homology and phylogenetic analysis, a newly isolated indigenous potential lipase producer strain was identified as uncultured Bacillus species clone W2 (Gene Bank Accession Number F5863099.1). In quest for developing superior high yielding strains, this strain was subjected to strain improvement by a two step random mutagenesis (UV and HNO2). In the first step of UV mutagenesis, the plates having less than 1% survival rate were selected and tested for the lipase production. One UV mutant designated as Lp10II showed 133.3% higher activity than the parent strain. This mutant was further subjected to HNO2 mutagenesis. Among HNO2 mutants, Lp10IIb and Lp10IIc exhibited enhanced lipase activity. Lp10IIb and Lp10IIc have exhibited 6.3 and 8.0 fold higher lipase yields respectively than the parent strain. These yields were several folds higher than the yields of original uncultured Bacillus species clone W2 (Lp10).