粪肠球菌HX-3-6产γ-氨基丁酸发酵条件的优化

Optimization of fermentation condition for production of γ-aminobutyric acid by Enterococcus faecalis HX-3-6

目的优化粪肠球菌HX-3-6产γ-氨基丁酸(γ-Aminobutyric acid,GABA)的发酵条件,提高GABA的产量。方法通过单因素试验和正交试验对产GABA的粪肠球菌HX-3-6发酵条件进行优化,采用Plackett-Burman(PB)试验设计法筛选产GABA的培养基主要影响因素,应用Box-Behnken设计及响应面分析对影响发酵产GABA的主要培养基因素进行优化;用最终优化的配方进行3次验证试验。结果最佳发酵条件为底物浓度30 g/L,起始pH 5.5,发酵时间72 h,温度35℃;PB法筛选出了培养基中有显著效应的4个因素为MnSO4﹒H2O、NaCl、柠檬酸三胺和葡萄糖,经Box-Behnken设计及响应面分析,确定该4个主要影响因素的最佳浓度分别为0.100 785、0.224 459、0.215 355及12.335 95 g/L。3次验证GABA的产量平均可达16.027 g/L,比优化前(11.006 g/L)提高了45.62%。结论优化的粪肠球菌HX-3-6发酵条件和培养基可显著提高GABA产量,为其工业化生产奠定了基础。

Objective To optimize the fermentation condition for production of γ-aminobutyric acid （GABA） by Enterococcus faecalis HX-3-6. Methods The fermentation condition of E. faecalis HX-3-6 producing GABA was optimized by single factor test and orthogonal test, based on which the main influencing factors of medium for production of GABA were screened by Plackett-Burman （PB） method, and optimized by Box-Behnken design and response surface method. Three validation tests were performed by using the optimized formula. Results The optimal substrate concen- tration, pH value, time and temperature for fermentation were 30 g/L, 5. 5, 72 h and 35 ℃ respectively. The main influencing factors of medium were MnSO4. H20, sodium chloride, citric acid triamide and glucose, of which the optimal concentrations were 0. 100 785, 0. 224 459, 0. 215 355, and 12. 335 95 g/L respectively. The mean yield of GABA in three validation tests reached 16. 027 g/L, which increased by 45. 62% compared with that before optimization （ 11. 006 g / L）. Conclusion The yield of GABA increased significantly by under the optimized fermentation condition, which laid a foundation of industrial production of GABA.