Increasing the Production of L-Asparaginase From Bacillus Licheniformis by Mutagenesis with Microwaves, Ultraviolet and Ethylmethanesulfonate (EMS).

L-asparaginase enzyme in food can prevent the formation of acrylamide by converting L-asparagine to aspartic acid. Acrylamide is a carcinogenic compound causing cancer. Enzyme biosynthesis could be improved by using random mutagenesis techniques. In this study, Bacillus licheniformis was exposed to microwave (MW) radiation at 2450 MHz for different exposure times (90–210 s). UV mutagenesis was performed at different distances (5–25 cm) from the exposure source (230 nm) for different exposure times (5–25 s). Ethylmethanesulfonate (EMS) (50–300 µg/ml) was also treated for different incubation periods (10–60 min). The best results were obtained in terms of enzyme activity, total activity, protein content and EA/PC ratio using asparaginase secreted by mutants induced by MW (150 s), followed by UV (10 cm 20 s), and then mutants induced by EMS (100 µg/ml 20 min), the mutant MW150 showed 543.69, 543.69, 171.44 and 317.30 fold improvements in enzyme activity (EA), total activity, protein content (PC) and EA/PC ratio respectively compared to the original isolate (B). The mutant induced by MW alone was stable after 16 generations.