Enhanced Production of Poly-γ-glutamic Acid by Bacillus licheniformis TISTR 1010 with Environmental Controls.

Abstract

Bacillus licheniformis TISTR 1010 was used for glutamic acid-independent production of poly-γ-glutamic acid (γ-PGA). A fed-batch production strategy was developed involving feedings of glucose, citric acid, and ammonium chloride at specified stages of the fermentation. With the dissolved oxygen concentration controlled at ≥50% of air saturation and the pH controlled at ~7.4, the fed-batch operation at 37°C afforded a peak γ-PGA concentration of 39.9±0.3gL-1 with a productivity of 0.926±0.006gL-1h-1. The observed productivity was nearly threefold greater than previously reported for glutamic acid-independent production using the strain TISTR 1010. The molecular weight of γ-PGA was in the approximate range of 60 to 135kDa.