Enhancement of poly‐γ‐glutamic acid production by alkaline pH stress treatment in Bacillus licheniformisWX‐02

BACKGROUND The effects of alkaline stress on γ‐ PGA biosynthesis and the mechanism involved have not been investigated in glutamate‐free medium. RESULTS Effects of alkaline pH stress on the yield and molecular weight of γ‐ PGA were investigated in a 50 L bioreactor, and transcriptional levels of relevant genes were measured to explain the mechanism. After alkaline stress treatment, the maximum γ‐ PGA yield reached 36.26 g L −1 , increased by 79%...