Production of alpha amylase from a randomly induced mutant strain of Bacillus amyloliquefaciens and its application as a desizer in textile industry

The present study is concerned with the improvement of bacillus amyloliquefaciens strain ung-16 for alpha amylase production. the bacterial culture was exposed to uv irradiation at 1.6×102 j/m2/s for 15-60 min. however,uv induced viables did not give improved alpha amylase production; therefore chemical mutation using ethyl methane sulphonate (ems 50-300 μl/ml) was undertaken for 10-60 min. the mutant b. amyloliquefaciens ems-6 gave 102.78±2.22 u/ml/min enzyme activity which was 1.4 fold higher than the parental strain. in stirred fermentor,the incubation period was reduced from 72 to 48 h after inoculation. the production of alpha amylase was found to be maximal when the 60% volume,2.0 vvm air supply and 400 rpm agitation rate was maintained during the fermentation period. the incubation temperature (37°c) and size of inoculum (8.0%) were also optimized. a 100% desizing of grey fabric (or starch removal) was obtained with 200-250 enzyme units at ph 6.5 at 60°c in 1 h.