富锌产γ-氨基丁酸乳酸菌的筛选及初步鉴定

用含0.2%-0.25%Zn^2＋的MRS培养基从发酵酸菜、酸奶中分离出6株具富锌能力细菌,经形态和生理生化特性鉴定,初步判断菌株为乳酸菌。采用纸层析检测MRSG培养基培养的6株菌上清液后,初步确定有4株能产γ-氨基丁酸。以此4菌株基因组为模板PCR扩增到540 bp的片段,经测序和序列分析,证明是谷氨酸脱羧酶基因高度保守区域,初步证明谷氨酸脱羧酶基因的存在。此4株菌发酵液经HPLC检测和分析后,证实2号菌株能转化谷氨酸钠生成GABA,产量为4.8 g/L,在应用方面具有很大的潜力。

Screening of the lactic acid bacteria strains with Zn-enriching and GABA-producing capacity and its preliminary identification

Six strains of bacteria with zinc-enriching capacity were isolated from yogurt and pickles with basic medium containing 0.2%-0.25% Zn^2＋,and were preliminarily identified as lactic acid bacteria by morphology and some biochemical characteristics.The four strains with γ-aminobutyric acid producing capacity were preliminarily screened by detecting the fermentation broth of the MRSG medium with paper chromatography.The 540 bp PCR products amplified from the four strains genome were sequenced and analysised,and fragments were proved to be the highly conserved region of glutamic acid decarboxylase gene. The result preliminarily confirmed the existence of glutamic acid decarboxylase gene. The strain No. 2 was verified to have the capacity of converting glutamate into GABA by HPLC after fermentation, and the GABA yield of the strain was 4.8 g/L. The result proved that this lactic acid bacteria strain with Zn-enriching and GABA-producing capacity has a great potential in application.