UC Davis

We investigated whether sucrose metabolism by probiotic Lactobacillus plantarum influences the intestinal survival and microbial responses to this organism when administered to mice fed a sucrose-rich, Western diet. A L. plantarum mutant unable to metabolize sucrose was constructed by deleting scrB, coding for beta-fructofuranosidase, in a rifampicin-resistant strain of L. plantarum NCIMB8826. The ScrB deficient mutant survived in 8-fold higher numbers compared to the wild-type strain when measured 24 h after administration on two consecutive days. According to 16S rRNA marker gene sequencing, proportions of Faecalibacterium and Streptococcus were elevated in mice fed the L. plantarum ΔscrB mutant. Metagenome predictions also indicated those mice contained a higher abundance of lactate dehydrogenases. This was further supported by a trend in elevated fecal lactate concentrations among mice fed the ΔscrB mutant. L. plantarum also caused other changes to the fecal metabolomes including higher concentrations of glycerol in mice fed the ΔscrB mutant and increased uracil, acetate and propionate levels among mice fed the wild-type strain. Taken together, these results suggest that sucrose metabolism alters the properties of L. plantarum in the digestive tract and that probiotics can differentially influence intestinal metabolomes via their carbohydrate consumption capabilities.