高产γ-氨基丁酸菌株的筛选鉴定及其在清香型白酒中的应用OA

High-yield γ-aminobutyric acid(GABA)strains were isolated and screened from fermented grains by traditional culture isolation method combined with HPLC-MS,and identified by morphological observation and molecular biological techniques,the superior strain with high-yield GABA was screened by environmental tolerance analysis,the fermentation process for GABA production was optimized by single factor experiments,and it was applied to small-scale brewing experiment of light-flavor(Qingxiangxing)Baijiu.The results showed that 2 strainswith high-yield GABA were screened and identified,which were Lentilactobacillus hilgardii X920 and Lentilactobacillus diolivorans X952.Among them,L.hilgardii X920 was a superior strain with high-yield GABA,which had good environmental tolerance.It could withstand temperature 47 ℃,pH 4.0,and ethanol volume fraction 12％.The optimized fermentation process for GABA production by L.hilgardii X920 was as follows:using MRS broth as the fermentation substrate supplemented with L-glutamate 50 g/L and glucose 20 g/L,incubation at 37℃ for 3 d.Under these conditions,GABA yield reached 29.53 g/L,which was 19.5 times higher than that before optimization.Adding 2‰ fermentation liquid of L.hilgardii X920(cell concentration 1×109 CFU/L)during the fermentation stage of light-flavor Baijiu could increase the GABA content in the fermented grains by 32 times,with the highest content reaching 0.48 g/kg.This research not only established a complete system for screening and fermentation process optimization of high-yield GABA strains,but also provided feasible process scheme for achieving targeted enrichment of GABA in fermented grains,and had significant industrial application value.