Screening and optimizing culture conditions of Bacillus strain for producing γ-polyglutamic acid.

γ-Polyglutamic acid producing strain yt102 was isolated from soils and taxonomically identified as Bacillus subtilis.A high productive strain of γ-polyglutamic acid was obtained from yt102 with mutagenesis by UV and NTG,and it was genetic ally stable in 10 generations.Fermentation medium composition for the mutant strain was optimized by a single factor and preliminary orthogonal experiments.The average yield of γ-polyglutamic acid reached 28.5 g/L on the optimized medium.