Enhancing fermented vegetable flavor with Lactobacillus plantarum and Rhodotorula mucilaginosa.

The formation of flavor in fermented vegetables is directly associated with the interactions among the resident microbial strains. This study explored the cooperative dynamics between Lactobacillus plantarum and Rhodotorula mucilaginosa in a simulated cabbage juice system. The obtained results indicated that the co-cultivation of these strains accelerated fermentation kinetics and enhanced lactic acid production. The strains achieved a balanced consumption of substrates within the co-fermentation system through the exchange of metabolites. Additionally, co-fermentation facilitated the synthesis of characteristic flavor compounds while reducing the levels of undesirable flavors. Growth monitoring and transcriptomic analysis revealed that L. plantarum, as the dominant strain, perceived the surrounding environment through quorum sensing signals and upregulated genes related to the synthesizing of key compounds, enhancing product yields and forming biofilms to adapt to the symbiotic environment. Conversely, R. mucilaginosa responded to the stress induced by L. plantarum via upregulating transporters of metabolites, genes related to antioxidant stress, and longevity regulating, ultimately achieving coexistence with L. plantarum. This research provides a comprehensive understanding of the interplay between microbial strains in modulating fermentation processes and flavor profiles in vegetable fermentation.