一株高产γ-氨基丁酸短乳杆菌的筛选、鉴定及发酵优化

Screening and Identification of a High γ-Aminobutyric Acid-Producing Lactobacillus brevis Strain and Optimization of Fermentation Conditions

为了筛选高转化γ-氨基丁酸(γ-aminobutyric acid,GABA)乳酸菌新菌株,本研究以谷氨酸钠为底物,以110株分离自传统发酵食品和鸡肠道中的乳杆菌为研究对象,利用薄层层析和Berthlot比色法进行筛选,结果表明菌株S6-4为GABA高产菌株,产量为1.98 g/L。该菌株经API CHL 50生化系统和16S rDNA序列分析鉴定为短乳杆菌(Lactobacillus brevis)。同时对影响菌株S6-4转化GABA能力的各因素进行初步优化,最终确定:MRS培养基中以牛肉膏和酵母浸粉作为氮源,按1 mg/L(w/v)添加Vit B6和Vit C作为促生长因子,培养基初始pH为6.5,27℃条件下培养36 h,菌株S6-4转化GABA的产量达到4.05g/L,提高了105%。

To find a high γ-aminobutyric acid-producing lactic acid bacterium, more than 110 strains of lacto-bacillis isolated from Chinese fermented foods and astrointestinal tract of chickens were screened using thin-layerchromatography and colorimetric methods with glutamic sodium as substrate. The results showed that strain S6-4 ex-hibited high GABA-producing ability with 1.98g/L, which was identified as L. brevis by API 50 CHL kit and 16 S r D-NA sequencing analysis. The factors on transformation of GABA ability of strain S6-4 were analyzed and finally de-termined as follows： MRS medium with beef extract and yeast extract as nitrogen source, subsequently added 1mg/L（w/v） Vit B6 and Vit C as growth factor, initial pH was 6.5, cultured for 36 h under the condition of 27℃, the GABAyield reached 4.05g/L and increased by 105%.