原生质体融合技术选育弱后酸化乳酸菌菌株的研究

Screening of the weak postacidification lactobacillus strains using protolast fusion technology

对新疆地方乳酸菌Lactobacillus bulgaricus LN1#进行原生质体融合,应用均匀设计的方法得到L.bulgaricus LN1#的原生质体制备条件:溶菌酶质量浓度为15.00 g/L,酶解细胞壁的时间为60 min,酶解温度为44℃。对原生质体进行灭活,致死率达到100%的条件:紫外线灭菌为120 s;高温为53℃,60 min。应用青霉素对融合子进行筛选,最终得到37℃培养时产乳酸量与出发菌株相同,10℃贮藏时,产乳酸量明显减少的目标菌株NO2#和NO3#。

Protolast fusion technology was used in Lactobacillus bulgaricus LNI# from Xingjiang to obtain the weak postacidification strains. Optimum preparation condition for protolast of L. bulgaricus LNI# was achieved using uniform design experiment, being cytoderm was zymohydrolysed with lysozyme concentration of 15.00 mg/mL at 44 ℃ for 60 min. The following 100% inactivation condition for protolast was attained with ultraviolet radiation for 120 s or high-temperature sterilizing at 53 ℃ for 60 min. Penicillin was used to screen the weak postacidification strains. L. bulgaticus NO2# and NO3# were elected as target strain, which have the same lactic acid production capacity with LNI# at 37 ℃,but less lactic acid production than at LNI# 10 ℃.