食品与发酵工业2024，Vol.50Issue(12)：101-108,8.DOI:10.13995/j.cnki.11-1802/ts.036908
嗜热链球菌937胞外多糖生物合成途径及表型分析
Biosynthetic pathway and phenotypic analysis of exopolysaccharide of Streptococcus thermophilus 937
摘要
Abstract
The exopolysaccharides produced by Streptococcus thermophilus during its growth can improve the texture of fermented dairy products and have various physiological and biochemical functions.To explore the regulatory mechanism of histidine,isoleucine,and glu-tamate on the exopolysaccharide of S.thermophilus 937,this study analyzed the exopolysaccharide synthesis pathway of the strain through whole genome sequencing.It then explored the effects of the concentration of 3 amino acids on the strain growth,the production and prop-erties of exopolysaccharides,and the transcription level of epsABCD of the strain.Results showed that the strain had a specific PTS for glu-cose and sucrose transport system and lactose osmotic enzyme.It had the potential to synthesize UDP-glucose,UDP-galactose,and dTDP-rhamnose.There was the eps gene cluster composed of 18 coding genes on the chromosome.When the concentration of 3 amino acids was increased to 15 mmol/L,the exopolysaccharide production of the strain increased by 1.5 times,the molecular weight increased by 1.2 times,the molar ratio of monosaccharide composition changed,and the epsABCD transcription level was significantly upregulated(P＜0.05).The 3 amino acids enhanced the production of exopolysaccharides and regulated the properties by regulating the expression of epsABCD.The results of this study provided a better understanding of the exopolysaccharide biosynthesis of Streptococcus thermophilus at the gene level.关键词
嗜热链球菌/胞外多糖/eps基因簇/氨基酸/转录调控机制Key words
Streptococcus thermophilus/exopolysaccharides/eps gene cluster/amino acids/transcription regulation mechanism引用本文复制引用
夏亚灵,徐欣,徐心怡,瓦云超,顾瑞霞..嗜热链球菌937胞外多糖生物合成途径及表型分析[J].食品与发酵工业,2024,50(12):101-108,8.基金项目
国家自然科学基金(31972094) （31972094）
市校合作共建科技创新平台(YZ2020265) （YZ2020265）
江苏省大学生创新训练项目(202311117014Z) （202311117014Z）
