嗜热链球菌半乳糖突变株的选育及其发酵特性  

Breeding and Fermentation Characteristics of Galactose Mutant Strains of Streptococcus thermophilus

作　　者：何彬彬 邰佳慧 卢纹慧 崔欣蕊 丹彤[1,2,3] HE Binbin;TAI Jiahui;LU Wenhui;CUI Xinrui;DAN Tong(Key Laboratory of Dairy Biotechnology and Engineering(IMAU),Ministry of Education,Inner Mongolia Agricultural University,Hohhot 010018;Key Laboratory of Dairy Products Processing,Ministry of Agriculture and Rural Affairs,Inner Mongolia Agricultural University,Hohhot 010018;Inner Mongolia Key Laboratory of Dairy Biotechnology and Engineering,Inner Mongolia Agricultural University,Hohhot 010018)

机构地区：[1]内蒙古农业大学乳品生物技术与工程教育部重点实验室,呼和浩特010018 [2]内蒙古农业大学农业农村部奶制品加工重点实验室,呼和浩特010018 [3]内蒙古农业大学内蒙古乳业生物技术与工程重点实验室,呼和浩特010018

出　　处：《中国食品学报》2025年第1期26-38,共13页Journal of Chinese Institute Of Food Science and Technology

基　　金：内蒙古自然科学基金面上项目(2022MS03013);国家自然科学基金项目(32072235)。

摘　　要：以分离自传统发酵乳制品中的嗜热链球菌IMAU80809为研究对象,利用亚硝基胍对菌株进行诱变处理。通过对与半乳糖代谢相关酶活性的测定、基因序列比对分析,筛选得到1株可代谢半乳糖的突变株——嗜热链球菌IMAU80809Y。在此基础上,制备嗜热链球菌IMAU80809和突变株发酵乳,分析发酵乳中pH值、滴定酸度、黏度、持水力、活菌数以及关键代谢产物的变化情况。研究结果表明,与原始株相比,突变株发酵乳的凝乳时间缩短至7 h,β-半乳糖苷酶和半乳糖激酶的活性分别提升了76.16%和21.13%,而丙酮酸激酶和葡萄糖激酶的活性分别下降了46.89%和18.83%。此外,与原始株相比,突变株发酵乳中乳糖和半乳糖的含量分别降低了0.599 g/100 g和0.208 g/100 g,说明其代谢乳糖/半乳糖的能力高于原始株。本研究的顺利进行为低半乳糖发酵乳制品的生产提供了理论依据。Streptococcus thermophilus is often used as a starter culture in the production of fermented dairy products.In this study,S.thermophilus IMAU80809 was selected as the research object and subjected to mutagenesis treatment with nitrosoguanidine(NTG).Through the determination of enzyme activities related to galactose metabolism and gene sequence alignment analysis,a mutant strain capable of efficiently metabolizing galactose,S.thermophilus IMAU80809Y,was screened out.On this basis,fermented milk of S.thermophilus IMAU80809 and its mutant strain was prepared,and the changes in pH value,titratable acidity,viscosity,water-holding capacity,viable cell count,and key metabolites were analyzed in detail.The results showed that compared with the wild type strain,the curdling time of the mutant strain's fermented milk was shortened to 7 h.The activities ofβ-galactosidase and galactokinase increased by 76.16%and 21.13%respectively.While the activities of pyruvate kinase and glucokinase decreased by 46.89%and 18.83%respectively.In addition,the metabolic amounts of lactose and galactose by the mutant strain increased by 0.599 g/100 g and 0.208 g/100 g respectively.These results indicate that the ability of the mutant strain to metabolize lactose and galactose was significantly higher than that of the wild-type strain.This study provides a theoretical basis for the production of low-galactose fermented dairy products.

关 键 词：嗜热链球菌 亚硝基胍 诱变 半乳糖 

分 类 号：TS252.1[轻工技术与工程—农产品加工及贮藏工程]