Quorum Sensing Regulates the Growth of <i>Ketogulonicigenium vulgare</i> During the Fermentation Process of Vitamin C

Quorum sensing (QS), a cell-density-dependent intercellular communication system, regulates bacterial gene expression and is widespread in microbial populations. However, the role of QS in the vitamin C fermentation consortium, comprising Ketogulonicigenium vulgare and Bacillus pumilus, remains unclear. This study analyzed QS-related gene expression in K. vulgare 25B-1 and B. pumilus during mono- and co-fermentation. We identified a novel quorum-quenching lactonase, YtnP, in B. pumilus, which degraded signaling molecules of 25B-1. YtnP inhibited QS-associated gene expression in 25B-1 and enhanced 2-keto-L-gulonic acid (2-KLG) production at high cell densities. Additionally, YtnP suppressed cell lysis and alleviated oxidative stress in 25B-1. These findings provided insights into interspecies communication in vitamin C fermentation and other more complex microbial consortia interactions.