γ-聚谷氨酸发酵工艺研究

摘要

采用发酵技术,利用枯草芽孢杆菌发酵生产γ-聚谷氨酸,对γ-聚谷氨酸发酵工艺进行研究.主要研究碳源、氮源、装液量、接种量、发酵时间、pH以及前体谷氨酸钠和促进剂氯化铵对γ-聚谷氨酸发酵的影响.前期研究表明,γ-聚谷氨酸发酵液黏度与其产量线性相关,故本研究中采用发酵液黏度作为γ-聚谷氨酸产量的衡量指标.通过单因素试验和正交试验,对发酵培养基和发酵条件进行优化,最后得到最佳发酵培养基配方和发酵条件.通过单因素及正交试验,确定最佳发酵培养基配方为:葡萄糖4%,酵母膏0.5%,谷氨酸钠3%,MgSO4·7H2O 0.025%,K2HPO4 0.2%,氯化铵0.3%;最佳发酵条件为:初始pH 9.5,装液量50mL,接种量6%,摇床转速为220 r/min,37℃振荡培养72 h.%In this study, the fermentation technology was used to produce γ-PGA with Bacillus subtilis fermentation, and the fermentation process technology ofγ-PGA is studied. The influence of the output ofγ-PGA was the main researched, such as the carbon source, nitrogen source, liquid volume, inoculation , fermentation time, pH and sodium glutamate precursor and the promoter of ammonium chloride. Previous studies had shown thatγ-PGA fermentation broth viscosity linearly related to its production , the viscosity of the fermentation broth was used as γ-PGA output measure. The optimum medium composition and the optimum fermentation conditions scope were determined by single factor experiment orthogonal experiment. The optimum medium of the fermentation obtained through the single factor and orthogonal experiments was:4%glucose, 0.5%yeast extract, sodium glutamate 3%, MgSO4 7H2O 0.025%, K2HPO4 0.2%, ammonium chloride, 0.3%;Optimum fermentation conditions were: initial pH 9.5, medium volume 50mL, inoculum size 6 %, rotation speed of 220 r/min, 37℃oscillator cultured 72 h.