Screening ofγ-Polyglutamic Acid High Productive Strain and Preliminary Optimization of Its Fermentation Medium

A high productive strain of γ-PGA was abtained from Bacillus subtilis of being preserved in our laboratory with mutagenesis by UV、NTG and 60Co γ-ray.Being cultivated in the basic fermentation medium,the production of mutant is 3.11 times of the riginal strain,and the mutant showed genetic stability during 10 generations;The fermentation mudium composition of the mutant was optimized by a preliminary orthogonal experiment.γ-PGA productivity of the mutant reached 33.81g/L by being cultivated in the optimum fermentation medium.The production in the optimum medium is 1.11 times of the basic medium.The flask fermentation production of the mutant is high and the mutant is worthwhile to studied further.