耐受乙醇乳酸菌诱变的研究

以面包乳杆菌（Lactobacillus crustorum D2-5）和植物乳杆菌（Lactobacillus plantarum D5-5）为研究对象，分别选取不同浓度乙醇胁迫处理后，进行诱变育种，探究经乙醇胁迫后乳酸菌诱变育种的耐受性；根据最佳诱变剂量的条件，确定最佳诱变方法；以乙醇胁迫处理后乳酸杆菌的生长曲线，验证乙醇胁迫后乳酸菌诱变菌株的耐受性。结果表明：添加与乳酸菌悬浮液等体积的1%硫酸二乙酯（DES）化学诱变效果最佳，最适诱变时间为40 min，乙醇胁迫过程中诱变菌株的生长速率有所提高，以体积分数8%乙醇胁迫为例，24 h时，D2-5菌落总数的对数值由6.2提高至7.3，D5-5菌落总数的对数值由6.9提高至7.1。说明诱变育种有助于乳酸杆菌乙醇胁迫耐受性的提高，并获得乙醇耐受特性较好的菌株D2-5。

Research on mutagenesis of ethanol tolerance lactic acid bacteria

Using Lactobacillus crustorum D2-5 and Lactobacillus plantarum D5-5 as the research object, they were selected by mutation after different concentrations of ethanol stress processing. The tolerance of lactic acid bacteria mutation breeding after ethanol stress processing was investigated. According to the optimum mutation dose, the optimum mutation method was determined. The tolerance of lactic acid bacteria mutant strain was verified by growth curve of lactic acid bacteria after different ethanol concentrations stress processing. The results shown that the optimum chemical mutagenesis was 1% diethyl sulfate added equal volume with lactic acid bacteria suspensions, the optimal mutagenesis time was 40 min, the growth rate of mutant strain was increased during ethanol stress processing. Taking 8% ethanol for an example, the Log value of strain D2-5 total bacterial count increased from 6.2 to 7.3, the value of strain D5-5 increased from 6.9 to 7.1 after 24 h. The study indicated that mutation breeding could improve the ethanol stress tolerance of lactic acid bacteria, and the strain D2-5 with high ethanol tolerance was obtained.