中文摘要：

为获得耐温和耐酸性能优良的乳酸菌广泛应用于工业化生产，从不同地方采集的样品中分离筛选出一株耐高温乳酸菌株作为出发菌株，采用He．Ne激光对其进行诱变处理，对激光诱变参数进行优化，考察了突变株的耐温性、耐酸性和遗传稳定性。在波长632．8nm，功率10mW，照射时间15min条件下，经初筛、复筛获得l株耐高温且产酸能力强的优良菌株L．2，70℃培养突变株菌数晕是出发菌株的9．4倍，菌数量多达15．56x10s个／mL，突变株的酸度值最终可达3．42，且其具有良好的遗传稳定性。

英文摘要：

In order to obtain the excellent lactic acid bacteria used for industrialization, a strain with high thermotolerance was isolated from silage, apple pomace, milk and fresh pickles from the different regions. Using the thermotolerant lactic acid bacteria as the original strain and He-Ne laser as the mutagen, To optimize the laser mutagenesis conditions, the thermotolerant, aciduric and heredity potential of the mutant were tested. When the wavelength was 632.8nm, the laser power was 10mW and the irradiation time was 15rain, a mutant with the thermotolerant and aciduric capability was obtained. The number of the mutant was 9.4 times than that of the original strain in the temperature 70~C. The number of bacteria increased to 15.56×10^8u/ml. The pH value was 3.42 finally. The mutant had the steady heredity.