新疆葡萄酒高产酸酿酒酵母菌的筛选和发酵条件优化

Screening of high-yielding acid yeast strains in Xinjiang wine producing regions and optimization of fermentation conditions

以从新疆阜康、昌吉、焉耆3个产区的葡萄和土壤中所筛选出的39株酵母菌为出发菌株,以便确定高产酸酿酒酵母筛选培养基配方及其灵敏性。通过初筛和复筛,获得1株产酸含量高的酿酒酵母Y6,结果表明该菌株的挥发酸含量与商业酵母菌株71B基本一致,并对产酸酵母菌的发酵条件进行优化。单因素试验确定了初始酸度、发酵温度和酵母菌接种量对酵母菌产酸能力的影响较为显著,选取这3个因素进行响应面优化,得到优化条件是:葡萄汁初始酸度为6.70 g/L、发酵温度为20.35℃、接种量为109CFU/m L,响应预测值达1.7664 g/L。同时,最佳优化条件下获得的实际值与预测值吻合,说明所建立的回归模型是切实可行的。在小型葡萄酒发酵生产试验中,与71B相比,酿酒酵母Y6产酸量提高了1.84 g/L。

39 yeast strains from three major wine-producing regions in Xinjiang including Changji, Manasi and Fukang were screened out to determine culture medium formulation and sensitivity of organic acids high-yielding Sac- charomyces cerevisiae. Through initial and repeated screening, 1 strain of Saccharomyces cerevisiae with high-yielding acids named as Y6 was screend out. The results showed that the volatile acid content of Saccharomyces cerevisiae Y6 was the same as that of commercial yeast strain 71B. Based on these single factor tests, response surface methodology with three variables was employed to optimize the fermentation conditions such as initial acidity, fermentation tempera- ture and inoculum amount. Results showed the optimal fermentation conditions were grape juice initial acidity of 6.70 g/L, fermentation temperature of 20.35 ℃ and inoculum amount of 10^9 CFU/mL. Under these optimal conditions, the acid production capacity reached 1. 766 4 g/L. Finally, the consistent results between the predicted value and ac- tual value indicated that the established model in this study was feasible. In a small scale of wine fermentation experi- ment, compared with the commercial strain 71 B, the acid production of Y6 was increased by 1.84 g/L.