Impact of Stropharia rugosoannulata extract on Lactobacillus reuteri HBM11-69 growth, metabolism and mechanisms

To promote the growth of Lactobacillus reuteri (L. reuteri), in this study, we optimized the culture using a single-factor experimental and response surface methodology. Then, the water extract of Stropharia rugosoannulata (WES) was used as an accelerant for L. reuteri HBM11-69 growth, and its effects on the growth and metabolism of the strain were investigated. Meanwhile, transcriptomics was used to analyze the gene expression of L. reuteri and its possible mechanisms. The optimal medium formulation for L. reuteri HBM11-69 was determined by single-factor experimental and response surface methodology, and the number of viable bacteria was 5 times higher than that of MRS medium. Furthermore, L. reuteri HBM11-69 exhibited the best growth with the viable bacterial number of 1.41×1010 CFU/mL and the content of short-chain fatty acids was the highest when 20 g/L of WES was added to the optimized medium. L. reuteri HBM11-69 cultures before and after WES addition were used for transcriptome analysis. The transcriptomic results showed that the differentially expressed genes BSU40060, BSU33510, spr1465 and BSU22120 were significantly up-regulated. The WES promoting proliferation of L. reuteri HBM11-69 is closely related to glucokinase, heavy-metal-associated domain-containing protein and phosphatidic acid biosynthetic.