植物乳杆菌1-9代谢水苏糖机制研究OA北大核心CSTPCD

A strain of Lactobacillus was successfully isolated from fermented goat milk and identified as Lactiplantibacillus plantarum 1-9,which could efficiently utilize stachyose as the carbon source.In order to investigate the mechanism for stachyose metabolization by Lactiplantibacillus plantarum 1-9,the growth curve was established with stachyose as the only carbon source.The production of short chain fatty acids was monitored by high performance liquid chromatography,while thin-layer chromatography were used to monitor the metabolic procedures of stachyose by Lactiplantibacillus plantarum 1-9.Besides,on the basis of monitoring the gene expression of key stachyose metabolizing enzyme,the changes of related enzyme activity in fermentation broth were analyzed.The results showed that Lactiplantibacillus plantarum 1-9 metabolized stachyose and produced acetic acid and valeric acid as the major short chain fatty acids,which reached the highest concentration of 28.64 mg/mL and 2.74 mg/mL,respectively.The accumulation of short-chain fatty acids resulted in a significant decrease of pH to 4.00.Based on the results of metabolic procedure of stachyose and changes of gene expression and enzyme activity,gene 5-359 in the genome of Lactiplantibacillus plantarum 1-9 might encode α-galactosidase.This segment could hydrolyze the α-galactoside bond at the end of stachyose and produce galactose and small amount of lactose and sucrose,thus facilitating the utilization of stachyose by Lactiplantibacillus plantarum 1-9.This study aimed to provide theoretical reference for the reasonable design of symbiotics based on Lactiplantibacillus plantarum and stachyose,and the development of related products.