黄水基质微生物发酵合成γ-聚谷氨酸培养基及条件优化

Culture Medium and Condition Optimization ofγ-Polyglutamic Acid Synthesized by Microbial Fermentation Using Yellow Water

以白酒酿造副产物黄水为基质,微生物发酵生产γ-PGA,以期为黄水的综合利用寻求一条新途径的同时,实现黄水的高值化利用。本文以黄水作为微生物发酵用基质,通过检测发酵液中γ-PGA浓度、发酵液粘度、残留谷氨酸及葡萄糖浓度,利用单因素及响应曲面设计试验优化黄水微生物发酵合成γ-PGA的培养基及条件,结果显示:pH为7.0、稀释8倍的黄水作为溶剂时,玉米糖化液浓度75 g/L(按可溶性固形物含量计),牛肉粉浓度70 g/L,谷氨酸钠浓度45 g/L,NaCl浓度12 g/L,K_(2)HPO_(4)浓度7 g/L,接种量1%,装液量25 mL/250 mL,37℃发酵72 h,γ-PGA产量达14.510 g/L。由此可见,黄水基质微生物发酵合成γ-PGA是可行的。

Yellow water,one of the by-products of Baijiu brewing.Microbial fermentation to produceγ-PGA using yellow water as substrate.This idea not only finds a new way for the comprehensive utilization of yellow water,but also realizes the high value utilization of yellow water.In this paper,the liquor by-product yellow water as the substrate for microbial fermentation,optimizing the culture medium and conditions of fermentation syntheticγ-PGA using single factor and response surface design experiments.Fermentation results were evaluated by measuringγ-PGA concentration,viscosity,residual glutamate and glucose concentration in fermentation broth.According to the results,when the pH value was 7.0 and the yellow water was diluted 7 times,Corn saccharification solution 75 g/L(by soluble solids content),Beef powder 70 g/L,Sodium glutamate 45 g/L,NaCl 12 g/L,K_(2)HPO_(4)7 g/L,the inoculation amount was 1%,25 mL/250 mL,at 37℃for 72 h,the yield ofγ-PGA was 14.510 g/L.Hence,it is feasible to synthesizeγ-PGA by microbial fermentation using yellow water as the substrate.