YtnP: One novel quorum quenching enzyme from Bacillus amyloliquefaciens W11 inhibits biofilms and spoilage of white radish by Serratia marcescens

Abstract

The spoilage of fruits and vegetables caused by microorganisms poses significant challenges to food safety and food industry. Serratia marcescens, a microorganism commonly found in the environment and food production facilities, exhibits strong spoilage activity on fruits and vegetables. In this study, one novel lactonase (YtnP) derived from Bacillus amyloliquefaciens W11 was successfully expressed and utilized to combat the spoilage of white radish caused by S. marcescens. The recombinant YtnP demonstrated broad-spectrum activity against various AHL signaling molecules. Notably, YtnP exhibited remarkable thermal stability, retaining over 60% enzyme activity after exposure to 75 °C for 1 h. Through mutagenesis of key amino acid residues, mutants H111A and H113A exhibited negligible enzyme activity against C6-HSL. H115A and H191A demonstrated reduced catalytic activity compared to the wild type. Conversely, mutant S154K exhibited enhanced catalytic activity against C6-HSL. Furthermore, infection models involving white radish and Galleria mellonella larvae confirmed that YtnP significantly reduced the toxicity of S. marcescens towards the host. Consequently, these findings highlight the potential of YtnP from B. amyloliquefaciens W11 as a food preservative against S. marcescens.