STRAIN IMPROVEMENT OF ISOLATED BACILLUS SUBTILIS STRAIN HSWX88 FOR EXTRACELLULAR L-ASPARAGINASE PRODUCTION

Abstract

The purpose of the present investigation is to enhance extracellular L-asparaginase production by subjecting Bacillus subtilis strain hswx88, isolated from Taptapani, a hot spring of Ganjam District of Odisha, India, to improvement by random mutagenesis by ultra-violet (UV) irradiation, Nitrous acid and N-Methyl-N’-nitro-N- nitroso guanidine (NTG) treatment. Mutants were screened as L-asparaginase producers on the basis of enzyme activity in submerged fermentation. UVS-5 mutant obtained after 18-20 minutes of UV exposure showed 1.25 times more enzyme activity (81.46 IU/ml). UVS-5 mutant further mutated by Nitrous acid and UVS5-N-6 mutant obtained after 210-240 Sec Nitrous acid exposure showed 1.59 times increase in enzyme activity (104. 06 IU/ml). Then UVS5-N-6 mutant was treated with NTG. UVS5-N-6-N-9 mutant obtained after 210-240 minute NTG exposure showed 2.03 times increase in enzyme activity (132.62 IU/ml) in compared to the isolated wild Bacillus subtilis strain hswx88 (65. 28 IU/ml). The results indicated that UV radiation, Nitrous acid and NTG were effective mutagenic agents for improvement of Bacillus subtilis strain hswx88. Thus these findings have more impact on enzyme economy by enhancing the production of extracellular L-asparaginase for anticancer applications.