高产γ氨基丁酸酿酒酵母的筛选及其在梨酒酿制中的应用

Screening of high γ- aminobutyric acid- yield yeast strains of Saccharomyces Cerevisiae and application in brewing of pear wine

从梨果实表面筛得到8株既能高产γ-氨基丁酸(GABA),又有较强产酒精能力的酵母菌株,其中菌株KS45产生GABA能力最强,达到了1.146 g/L。经鉴定,菌株KS45为酿酒酵母。当在含有梨汁的发酵培养基中静置发酵时,酿酒酵母KS45高产GABA,这表明梨汁中可能含有刺激酵母合成GABA的物质。将酿酒酵母KS45接种到鸭梨汁中,30℃下静置发酵10 d,获得了富含GABA的梨酒,其中GABA含量达到了2.427 g/L。实验发现,在富含GABA梨酒发酵过程中,GABA的产生伴随着酒精的消耗,呈现耦合关系,其机理尚不清楚。随着发酵温度的升高,梨酒的最终酒精度显著降低。装液量对GABA产生有很大影响。随着装液量的增加,梨酒中GABA含量急剧下降,这可能与氧气供给不足有关。

Eight yeast strains which could produce high yield of γ-aminobutyric acid （GABA）and ethanol were screened from the surface of pear fruits, among which, yeast strain KS45 had the highest capability of GABA production（1.146 g/L）.Strain KS45 was then identified as Saccharomyces cerevisiae.When S.cerevisiae KS45 was cultivated in pear juice-contained culture media,it could produce high yield of GABA in anaerobic condition,which indicated that pear juice might had compounds that could stimulate S.cerevisiae KS45 to produce GABA.After S. cerevisiae KS45 was inoculated in Ya pear juice and fermented in a incubator at 30 ℃ for 10 d, pear wine with rich GABA（2.427 g/L）was obtained.It was found that GABA production was coupled with ethanol consumption during the brewing of pear wine,and its mechanism was not clear.The final ethanol concentration of pear wine decreased significantly as the fermentation temperature increased.The volume of culture medium in the fermentor could affect the production of GABA.With increasing of the volume of culture medium, GABA concentration of the pear wine rapidly decreased,and the possible reason was that supply of oxygen was not sufficient.