Lactic acid bacteria isolated from Thai fermented pork, pickled mustard greens and pickled spring onions and their lifespan-extending potentials in Caenorhabditis elegans

Background: Fermented foods are natural sources of probiotics, especially lactic acid bacteria (LAB).LAB provide health benefits through modulating gut microbiota, improving immune function, boosting antioxidative capability, and extending lifespan. Objectives:To isolate LAB from Thai fermented foods and examine their lifespan-extending effects in Caenorhabditis elegans (C.elegans) model.Methods: Bacteria were isolated from Thai fermented pork (Neam), pickled mustard greens (Pak Gard Dong), and pickled spring onions (Ton Hom Dong).LAB were screened by the production of clear zone on CaCO 3 -containing MRS agar.One isolate was selected from each food source for further testing.Gram stain and 16S rRNA sequencing were carried out for LAB identification.The lifespan-extending effect of each LAB strain was investigated in the C. elegans model. Results:Three colonies of LAB, with obvious clear zone formation, were isolated and selected from Thai fermented pork, pickled mustard greens, and pickled spring onions.Gram stains showed that they were gram-positive bacilli.16S rRNA sequencing revealed that LAB isolates from fermented pork, pickled mustard greens, and pickled spring onions were Lactiplantibacillus pentosus (99.72%),Lactiplantibacillus pentosus (99.79%), and Lactiplantibacillus argentoratensis (99.24%), respectively.Lifespan of C. elegans fed with OP50 and LAB isolates, particularly Lactiplantibacillus pentosus from Neam, significantly increased compared with C. elegans fed with OP50. Conclusion:Lactiplantibacillus pentosus isolated from Thai fermented pork (Neam) could significantly extend the lifespan of C. elegans.This probiotic LAB strain could be beneficial for promoting longevity in humans.