Quorum-quenching potential of Limosilactobacillus fermentum UAS LAB 6 oxidoreductase against dairy spoilage and plant pathogenic Pseudomonas sp.: A computational perspective

Quorum-sensing (QS) regulates bacterial communication through N-acyl homoserine lactones (AHLs), which coordinate critical functions such as biofilm formation, virulence and spoilage activity. Disruption of this signaling, termed quorum-quenching (QQ), offers a sustainable strategy to mitigate pathogenicity without promising resistance. In this study, Limosilactobacillus fermentum UAS LAB 6, a lactic acid bacterium with known probiotic potential, was investigated for its ability to produce oxidoreductase enzymes capable of AHL modification. Whole-genome sequencing and annotation revealed multiple oxidoreductase candidates, of which a short-chain dehydrogenase/reductase (SDR) was selected for in silico characterization. Active site prediction and molecular docking analyses were performed using AutoDock Vina in PyRx 1.2 to evaluate enzyme interactions with AHL molecules produced by Pseudomonas fluorescens, P. syringae and P. corrugata. Docking results demonstrated high binding affinities, particularly between the SDR enzyme and 3-oxo-C14-HSL (ΔG = -7.4 kcal/mol), indicating strong substrate-enzyme interactions. The oxidoreductase exhibited a substrate preference toward long-chain and 3-oxo-substituted AHLs, consistent with its potential role in reducing the C3-oxo group to inactive 3-hydroxy derivatives. These findings suggest that L. fermentum oxidoreductases may effectively interfere with AHL-mediated signaling in plant-pathogenic and dairy spoilage Pseudomonas spp. Overall, this study highlights the dual quorum-quenching potential of LAB-derived oxidoreductases, offering an eco-friendly strategy to enhance plant health and food safety and through microbial signal disruption.