STRAIN IMPROVEMENT THROUGH MUTAGENESIS AND OPTIMIZATION OF PROTEASE PRODUCTION BY ASPERGILLUS TERREUS CJS-127 USING JATROPHA SEED CAKE AS SUBSTRATE

摘要

Jatropha curcas seedcake (JSC), a byproduct of the biodiesel industry was utilized for the production of protease. To enhance the protease production, the parent strain of Aspergillus terreus CJS-127 subjected to UV (15, 30, 60, 90, 120 and 150 min) and chemical mutagenesis by using ethyl methanesulphonate (EMS-125, 250 and 500 mg). Two mutant strains designated as UV-6 and EMS-5 selected for optimization of protease production using JSC medium by submerged fermentation. Under the optimized conditions of pH 7.0, temperature 30°C, incubation period 72 h, inoculum 105/ml spores, 150 rpm agitation, JSC at 2% level, the maximum protease production was 172.32 and 163.57 U/ml for EMS-5 and UV-6 mutant strains respectively. The addition of maltose (2%) was found to enhance the protease production in the mutant strains. The protease activity increased by 2.30 and 2.41 folds for UV 6 and EMS 5 mutant strains after optimization of cultural conditions.