Screening and Fermentation Medium Optimization of Lactobacillus γ-aminobutyrate in Black Soil of Cold Region

The lactic acid bacteria producing γ-aminobutyric acid(GABA)strains were screened from the black soil of Mudanjiang,Mohe and Wuchang by MRS medium,and their morphological observation,physiological and biochemical identification were carried out,and the fermentation medium composition was optimized. Experiments were performed to analyze the effects of different carbon sources,nitrogen sources,carbon to nitrogen ratios,initial pH and L-glutamic acid concentration on GABA production. The results showed that five strains were examined,which were numbered SbO001,SbO002,SbO003,SbO004 and SbO005. Five strains could be initially identified as Streptococcaceae.When the carbon source of fermentation medium was glucose,the nitrogen source was ammonium sulfate,the carbon-nitrogen ratio was 1:1,the initial pH was 5.5,and the substrate was 1% l-glutamic acid,the strain had a good gaba-producing capacity of 1.112 g/L.This experiment will provide some theoretical basis for the screening of lactobacillus GABA in the middle black soil of the cold region.