分子生物学法快速筛选具有优良产酸特性的嗜热链球菌

Rapid Screening Streptococcus thermophilus Strains with Superior Acid-Producing Character by Molecular Biology Techniques

目的:嗜热链球菌具有优良的发酵特性及生物学功能,是发酵乳制品中常用的发酵剂之一。由于高产酸菌株有助于提高生产效率,因此在工业生产中备受亲睐。方法:通过发酵乳的发酵试验,结合分子生物学技术对分离自自然发酵乳产品中的28株嗜热链球菌进行了筛选。结果:共筛选出5株高产酸菌株,分别是IMAU80844、IMAU80809、IMAU10636、IMAU80287、IMAU80846。基于产酸基因序列构建的系统发育树与发酵试验结果一致,可将高产酸菌株和低产酸菌株区分开,进一步验证了结果的可靠性。结论:本试验结果证实分子生物学方法能够快速筛选具有优良产酸特性的嗜热链球菌菌株,为今后筛选高产酸菌株提供新思路。

Objective： Streptococcus（S.） thermophilus, with excellent fermentation features and biological functions,is a major dairy starter used in fermented milk production. Because of the high efficiency of lactate production, S. thermophilus strain, with good acid-producing capacity, is suitable to be used in the dairy industry. Methods： In present study, twenty-eight strains of S. thermophilus, isolated from naturally fermented dairy products, were screened through the fermentation experiment combined with the techniques of molecular biology. Results： The results showed that five S.thermophilus strains, with good acid-producing capacity, were screened to be further used as dairy starter in dairy industry, including IMAU80844, IMAU80809, IMAU10636, IMAU80287 and IMAU80846. The results of phylogenetic tree, constructed based on the sequences of lactate-producing genes, indicated that all the high acid-producing strains were clustered together, which were clearly separated with the low acid-producing strains. This result was consistent with the results of fermentation experiment, making it more reliable. Conclusion： The results provide us a new idea that molecular biology techniques may be more rapid to screen out an industrial strain, with good acid-producing character.