Inhibition of Shewanella putrefaciens biofilm by laurel essential oil and its potential mechanisms

Shewanella putrefaciens (S. putrefaciens) is a major spoilage bacterium in aquatic products and has strong capacity to form biofilm, which contributes to its contamination and persistence in food system. The study aimed to investigate the effect of laurel essential oil (LEO) on biofilm formation of S. putrefaciens by phenotypic analysis and explore its potential mechanisms using RNA sequencing (RNA-seq) analysis. LEO significantly reduced biofilm formation in laboratory media and food broths (oyster juice and sea bass juice), as well as on shrimp surfaces and different food contact surfaces (304 type stainless steel, glass and food-grade silicone). Moreover, LEO also inhibited bacterial motility, decreased extracellular polymeric substances (EPS) contents, and modified biofilm structure. Additionally, RNA-seq analysis identified 229 differentially expressed genes (DEGs), which were involved in transcriptional regulation, multidrug efflux pump transporter, ribosome, cell motility, environmental factors and two-component systems. In conclusion, these findings identify LEO as a potential natural antibiofilm agent for S. putrefaciens and provide insights into its anti-biofilm mechanisms.