紫外诱变法选育酒酒球菌乙醇胁迫耐受菌株及其发酵性能研究

该研究以酒酒球菌（Oenococcus oeni）SD-2a为研究对象，采用紫外诱变法选育乙醇胁迫耐受突变菌株，评价其在乙醇胁迫条件下的生长能力，并测定其产β-葡萄糖苷酶活性及其在模拟酒中苹果酸、乳酸含量及活菌数的变化。结果表明，分离筛选到3株乙醇胁迫耐受性好的突变菌株，分别编号为UVe1、UVe2、UVe3，在高体积分数乙醇（12%和14%）胁迫环境下，3株突变菌株的生长速度均显著高于出发菌株SD-2a（P＜0.05）；突变菌株UVe2的β-葡萄糖苷酶活性显著高于出发菌株SD-2a和对照菌株L-450（P＜0.05）；在模拟酒中，3株突变菌株的苹果酸降解与乳酸生成速度均显著高于出发菌株SD-2a（P＜0.05），且突变菌株UVe1和UVe2的存活率显著高于出发菌株SD-2a（P＜0.05）；综上，突变菌株UVe2具有优良商业酒酒球菌的潜力。

Breeding of Oenococcus oeni strain with ethanol tolerance by UV mutagenesis and its fermentation performance

Using Oenococcus oeni SD-2a as the research object, the mutant strain with ethanol tolerance was bred by ultraviolet (UV) mutagenesis. The growth ability of the mutant strain under ethanol stress was evaluated, and the β-glucosidase activity, the changes in malic acid, lactic acid content and viable count in simulated wine fermented by the mutant strain were detected. The results showed that 3 mutant strains with good tolerance to ethanol stress were isolated and screened, numbered as UVe1, UVe2 and UVe3. The growth rate of 3 mutant strains were significantly higher than that of the starting strain SD-2a under high volume fraction ethanol (12% and 14%) stress (P＜0.05), and the activity of β-glucosidase of the mutant strain UVe2 was significantly higher than that of the starting strain SD-2a and control strain L-450 (P＜0.05). The degradation rate of malic acid and production rate of 3 mutant strains in simulated wine were significantly higher than that of the starting strain SD-2a (P＜0.05), and the survival rate of the mutant strains UVe1 and UVe2 were significantly higher than that of the starting strain SD-2a (P＜0.05). In summary, the mutant strain UVe2 had the potential of superior commercial O. oeni.