Metabolomics analysis reveals differences in milk metabolism and fermentation rate between individual Lactococcus lactis subsp. lactis strains

The bacterial starter has a crucial role in fermentation of dairy products; however, knowledge about metabolic differences in Lactococcus (L.) lactis subsp. lactis strains with different fermentation rates is limited. We analyzed the fermentation capacity and metabolic profiles of 17 L. lactis subsp. lactis strains through ultra-performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry Elevated Energy. Metabolomics results revealed significant differences in metabolites between the fast group (fermentation time < 16 h) and slow group (fermentation time ≥ 16 h). In the fast group, 98 and 55 metabolites were increased and decreased, respectively. The fast group was enriched with peptides and lipids, and we found that peptides, esters, and tributyrin can be used as biomarkers to distinguish between groups. Our results implicated that tributyrin plays a role in regulating strain growth. This study provides a novel insight into the metabolic cause of different acid production rates between individuals L. lactis subsp. lactis strains.