Profiling of Metabolite Changes in Lettuce Leaves during Fermentation by <i>Bacillus subtilis</i>

Metabolic profiling is a valuable tool for elucidating the biochemical pathways and key metabolites involved in the health benefits associated with microbial fermentation. In this study, we investigated the metabolic changes occurring during the fermentation of lettuce leaves by <i>Bacillus subtilis</i>, a widely studied bacterium known for its diverse metabolic capabilities. Through non-targeted metabolic profiling, we identified and characterized metabolites that may contribute to the beneficial effects of fermented lettuce. Using gas chromatography-mass spectrometry (GC/MS), we identified 54 metabolites in the fermented lettuce samples. Additionally, we elucidated the alterations in metabolite profiles during the bioconversion of lettuce using <i>B. subtilis</i>. Notably, 11,14-eicosadienoic acid, 13-docosenoic acid, and oleic acid were either produced or enriched during bioconversion, were identified as potential contributors to the enhanced nutritional and bioactive properties of fermented lettuce. This study underscores the potential of metabolic profiling to uncover the metabolic pathways and specific metabolites associated with health benefits in fermented foods. These findings pave the way for developing functional foods with improved nutritional value and bioactivity.