前期筛选获得1株高效转化L-谷氨酸为γ-氨基丁酸(GABA)的植物乳杆菌(Lactobacillus plantarum)GB01-21,该菌以浓度200 g/L的L-谷氨酸为底物,发酵20 h左右,能以99%的摩尔转化率生产γ-氨基丁酸,产物γ-氨基丁酸的终浓度可达140 g/L左右。从全细胞转化液中分离纯化γ-氨基丁酸,着重对脱色工艺进行了研究,考察了温度、时间、pH和活性炭添加量对脱色效果的影响。通过单因素实验的基础上的正交实验分析,确定了脱色最佳工艺条件为粉末活性炭(150～200目)用量为1.5%,脱色温度70℃,pH值4.0,脱色时间40 min,γ-氨基丁酸转化液的脱色率高达98.42%,γ-氨基丁酸的保留率可达97.23%。随后对γ-氨基丁酸转化液进行初步分离纯化,最终测得γ-氨基丁酸的回收率89.4%,纯度为96.7%。

A strain named Lactobacillus plantarum GB01-21 that can produce γ-aminobutyric(GABA) efficiently was screened in our laboratory.During the 20 hours,200 g/L L-Glu can be transformed into 140g/L GABA.In this work,γ-aminobutyric was separated and purified from the whole-cell transforming solution.The decolorizing technical conditions such as temperature,time,pH and amount of active carbon were studied.As a result,the optimum decolorization conditions were determined through single factor and orthogonal experiments as follows: activated carbon dosage 1.5%,decolorization temperature 70 ℃,pH value 4.0 and decolorization time 30 min.Under these conditions,the decolorization rate and recovery rate of bioconversion broth reached 98.42% and 97.23%,respectively.Finally,γ-aminobutyric acid was isolated and purified from bioconversion broth and the recovery rate and the purity of γ-aminobutyric acid was 89.4% and 96.7%,respectively.These findings pave the way for industrial production of GABA.