Optimization of γ-polyglutamic acid production process based on reed hydrolysate fermentation

Abstract

In order to reduce the production cost of γ-polyglutamic acid (γ-PGA) and realize high-value utilization of renewable resources such as reed, the feasibility of establishing a new fermentation process control strategy for the preparation of γ-PGA using reed hydrolysate as carbon source was explored. Firstly, the effects of cellulase dosage and substrate concentration on reed hydrolysis were studied; Secondly, the process of fermentation and production of γ-PGA from reed hydrolysate was optimized by segmented culture and DO feed-back control strategies. The results show that after pretreatment, the total sugar concentration of reed could reach (7664±174)g/L under the condition of 10 FPU/g (substrate) enzyme dosage and 10% substrate addition; the reed hydrolysate was produced γ-PGA by segmented dissolved oxygen feedback-batch feed fermentation culture, and the final yield could reach (4672±118])]g/L, with the production efficiency increasing by 4606% compared with batch fermentation. The use of reed hydrolysate for batch fermentation of γ-PGA is industrially feasible, which helps to reduce the raw material cost of its commercial production.

Keywords

• fermentation engineering; reed hydrolysate; γ-polyglutamic acid (γ-pga); fed-batch; do feed-back