高产γ-氨基丁酸酵母菌的筛选、鉴定及优化

Screening,Identification and Optimizing of γ-Aminobutyric Acid Production in Yeast

从新疆特色食品中筛选出能产γ-氨基丁酸的酵母菌菌株,并对其发酵条件进行优化。采用非酿酒酵母菌分离纯化的方法分离出非酿酒酵母菌,再通过初筛、复筛及诱变挑选出高产γ-氨基丁酸的菌株,并对其进行形态学及26S r RNA基因分析,最后对菌株产γ-氨基丁酸的发酵条件进行优化。经26S r RNA基因序列分析鉴定为葡萄汁有孢汉生酵母XYN019(H.uvarum XYN019);通过紫外诱变产量提高了2.3倍,最佳诱变时间为30 s,诱变浓度为10-5;优化后的理论发酵条件为培养温度33.95℃,pH值5.01,培养时间49.17 h,接种量为体积分数3.17%,其γ-氨基丁酸质量浓度达到4.926 g/L。以上结果表明,该菌株可作为γ-氨基丁酸产生菌,具有较好的γ-氨基丁酸生产潜力。

A strain with capability of producing γ-aminobutyric acid was isolated from the traditional food in Xinjiang and the fermentation conditions were optimized. Non-Saccharomyce yeast were isolated and further used to screen the strain with high yield of γ-aminobutyric acid. The isolated strain was identified as Hanseniaspora uvarum XYN019 by morphology and phylogenetic analysis based on the 26S rRNA sequence. The activity of amino acid production was 2.3 times higher as compared with the original one by UV mutagenesis. The optimum mutagenesis conditions are with 30s irradiation and 10-5 concentration. The better transformation conditions as follows：initial pH 5.01,culture temperature 33.95 ℃,inoculum size 3.17% and culture time 49.17 h. In this condition,the yielding capacity of GABA by the mutant was 4.926 g/L. These results suggested that the strain can be used to produce γ-aminobutyric acid and has a higher converting capability of GABA.