| Abstract [eng] |
Traditional Lithuanian fermented foods host diverse microbiota that may harbour probiotic and synbiotic lactic acid bacteria (LAB), a largely unexplored resource. This dissertation aimed to isolate, identify and characterize novel probiotic LAB from Lithuanian fermented foods and evaluate the best candidate in a mouse model of metabolic dysfunction. Of 150 LAB isolates from fermented pear, cherry tomato, cucumber, sauerkraut, kombucha and green beans, in vitro screening for gastrointestinal survival, adhesion and antimicrobial activity identified ten candidates from five genera. Genome sequencing revealed genes for stress tolerance, adhesion and tryptophan biosynthesis; safety screening confirmed five strains free of virulence factors and transferable resistance. Lacticaseibacillus paracasei 11W combined strong gastrointestinal tolerance and adhesion with the highest synbiotic L-tryptophan production with galacto-oligosaccharides (GOS). In a 25-week high-fat-diet mouse model, it reduced metabolic dysfunction, neuroinflammation and anxiety- and depressive-like behaviour, and increased Bifidobacterium abundance, supporting its potential as a synbiotic candidate for metabolic and neuroinflammatory disorders. |
