Screening and Identification of Lactobacillus Producing GABA and Study on the Fermentation Conditions

In order to screen lactic acid bacteria with high production capacity of γ-amino butyric acid(GABA),the traditional fermented food was selected as the source of bacterial strains in this study. The GABA production of 20 lactic acid bacteria strains was measured by thin layer chromatography(TLC)and high performance liquid chromatography(HPLC). The strain with high production capacity of GABA was identified and its factors influencing the production of GABA were studied. The results showed that a strain 14# of high production GABA was isolated from traditional fermented food,and the GABA content in the fermentation liquid reached 2.30 g/L. Then the strain 14# was identified as Lactobacillus plantarum by identification of colony morphology,physical,biochemical and 16S rDNA sequence. Finally,the factors influencing the production of GABA were determined and the fermentation optimization conditions were determined as follows:15 g/L glucose was used as the carbon source,and 10 g/L yeast powder and 15 g/L beef extract were used as the composite nitrogen source,and 1.5% L-glutamate was added in the MRS basic fermentation medium. The inoculum size was 4%,the initial pH was 6.0,and the culture was carried out at 37 ℃ for 48 h. The GABA content of optimization reached 9.12 g/L,which was nearly three times higher than the pre-optimized yield(2.30 g/L).