γ-聚谷氨酸提取条件的优化

Optimization of γ-polyglutamic acid extraction conditions

目的:通过实验对γ-聚谷氨酸提取条件进行优化得到一组产量高的最优条件。方法:利用枯草芽孢杆菌通过发酵生产得到含有γ-聚谷氨酸的发酵液,再以异丙醇作为沉淀剂提取发酵液中的产物。通过响应曲面分析方法设计三因素三水平Box-Behnken实验优化提取条件。最后利用薄层色谱和红外光谱对产物进行结构鉴定。结果:利用Design-Expert软件处理数据并优化得到一组最佳提取条件:异丙醇的添加倍数为4.5,沉淀温度为-5℃,沉淀时间为23h。在最优条件下得到γ-聚谷氨酸的产量为0.1796g/10mL,预测精确度达99%。结论:在低温下用异丙醇沉淀发酵液中的产物是一种有效可行的提取γ-聚谷氨酸的方法。

Objective：Experiments on the extraction of γ-Polyglutamic acid （γ-PGA） were optimized to get an optimal condition for high yield.Methods：γ-PGA was included in the fermentation fluid which was produced by Bacillus subtilis.Isopropanol was the precipitating agent which was used to extract the product from the fermentation fluid.A Box-Behnken design was used to evaluate the extraction effects of the three related factors.At last,thin layer chromatograph and infrared spectroscopy were used to identify the structure of γ-PGA.Results：Design-Expert software was used to process data and optimize the extraction conditions.The optimal isopropanol addition was 4.5 times of the zymotic fluid volumes,the optimal sedimentation temperature was-5℃,the optimal sedimentation time was 23h.Under the optimum condition,the production of γ-PGA was 0.1796g/mL,the precision of prediction run up to 99%.Conclusion：At low temperatures taking the precipitating agent with isopropanol to extract γ-PGA from the fermentation fluid was a practical and effective method.