乳酸乳球菌生产γ-氨基丁酸条件的优化

Optimization of Conditions for the Production of γ-Aminobutyric Acid by Lactococcus lactis

采用析因设计和中心组合试验设计对乳酸乳球菌FJNU-GA1304产γ-氨基丁酸(γ-aminobutyric acid,GABA)的条件进行优化。完全析因设计优化后的细胞转化条件为:p H 3.5、反应温度40℃、反应时间24 h,谷氨酸钠质量浓度20 g/L和湿菌体质量浓度25 g/L;在单因素试验的基础上,通过筛选设计确定谷氨酸钠、玉米浆粉和葡萄糖质量浓度为主效因子。采用三因素三水平的中心组合试验对主效因子的交互作用进行分析,结果表明:最佳的培养基组成为谷氨酸钠9.50 g/L、玉米浆粉12.50 g/L、葡萄糖5.74 g/L、酵母膏5.00 g/L、K2HPO4 1.20 g/L、Mg SO4 0.60 g/L。在最佳转化条件和发酵培养基组合下,GABA产量最高达9.06 g/L,比优化前4.80 g/L提高了88.8%。

Factorial design and central composite design were applied to optimize the yield of γ-aminobutyric acid(GABA) produced by cultured Lactococcus lactis cells from monosodium glutamate in a buffer solution. A full factorial design was used to optimize the conversion conditions as 40 ℃, p H 3.5 and 24 h. Using single factor designs, sodium glutamate, corn steep powder and glucose concentration were identified as major factors affecting GABA production. The interaction effect of the major factors at three levels each was analyzed by central composite design. The results showed that the optimal medium for Lactococcus lactis consisted of 9.5 g/L sodium glutamate, 5.74 g/L glucose, 12.50 g/L corn steep powder, 5.00 g/L yeast extract, 1.20 g/L K2HPO4 and 0.60 g/L Mg SO4. Under these conditions, the yield of GABA was 9.06 g/L, which was increased by 88.8%when compared with that(4.80 g/L) before optimization.