pH Control Strategy in the Polysiaic Acid Fermentation Production by Escherichia coli CCTCC M208088

Abstract:

Effect of the different pH control strategies on the PSA production by Escherichia coli CCTCC M208088 was compared in this study.Those strategies including:(1)when 20 g/L K2HPO4 was presented in the medium,the titer of PSA achieved at 1.9 g/L PSA,however,the high-level residual K2HPO4 in broth bring difficult to the following PSA purification.(2)with 2.5 g/L K2HPO4 and feeding of 2 mol/L NaOH solution,the titer of PSA was 2.3 g/L;(3)the PSA titer was increased to 3.2 g/L by feeding of ammonia water as pH control agent.Furthermore,the feeding of ammonia could accelerated sorbitol consummation;(4) To further promote PSA production,a novel strategy using ammonia water for pH control coupling with sorbitol supplementation at a constant feeding speed was adopted.As a result,PSA production and productivity were increased separately to 4.8 g/L and 0.16 g/(L·h),which was 152% and 188% higher than that of the control(without pH control).