β-galactosidase producing Lactiplantibacillus spp in intestinal microbiome mouse diarrhea model and metagenomic analyses

Probiotics have attained significant interest in recent years as a result of their gut microbiome modulation and gastrointestinal health benefits. Numerous fermented foods contain LAB with GRAS grade and probiotic bacteria. The most promising isolates with high potentiality were selected for 16S rRNA gene sequence analysis and identified as Lactiplantibacillus plantarum , L. fermentum , L. pentosus and Lactiplantibacillus sp. The present study was conducted to determine the gastrointestinal symptoms after the consumption of milk and dairy products, lactose intolerance status using mice model. Post-weaning Balb/c mice were orally administered with probiotic bacteria to assess their efficiency in reducing lactose intolerance symptoms. They exhibited significantly reduced total feces weight and slower intestinal motility and they efficiently alleviated diarrhea symptoms within 6 h of lactose challenge in lactose intolerance-induced mice. Next generation sequence analysis was performed using intestinal content of model treated with L. plantarum GV54 and GV64, the intestinal bacterial diversity was studied using Illumina NGS analysis (16S rRNA hypervariable regions [V3 and V4]). NGS report confirmed the existence of the dominant phyla of the gut microbiome in mice are Bacteroidetes, Firmicutes and Proteobacteria. Due to the influence of the probiotic bacteria in the model group (GV54 and GV64), maximum abundance of phylum Firmicutes were observed when compared to the control group, whereas control group showed more abundance of phylum Bacteriodetes. However, the relative abundance of Bacteroidetes in the model group was decreased and Firmicutes abundance was increased. This indicates the genus abundance of Lactobacillus ( Lactiplantibacillus ) species or Lactiplantibacillus plantarum GV54 and GV64 bacteria. After treatment with probiotic bacteria Lactobacillus ( Lactiplantibacillus ) species, the probiotic bacterial abundance was increased consequently genera Helicobacter, Clostridiales unclassified and Desulfovibrio were decreased in the model groups. Probiotic bacteria has a positive impact on the regulation of intestinal microbial diversity in the tested mice system and it reflects that the intestinal microbiota of mice is dynamic and has positive impact on gut health. Considering this point, it is possible to promote Lactiplantibacillus spp. as probiotics and therapeutic food development at industrial scale. • Lactose intolerance (LI) is caused by β-galactosidase deficiency. • Potential Probiotics like Lactoplantibacillus sp was used to decrease LI. • Total microbiome analysed by illumina sequencing determined the dominance of Firmicutes. • Indigenous Lactiplantibacillus and Limosilactobacillus strains have produced β-galactosidase enzyme LI. • Probiotic bacteria positively impacted the regulation of intestinal microbial diversity, indicating dynamic intestinal microbiota.