Production of lipase and extracellular polymeric substances by the lipid-degrading bacterium Burkholderia arboris strain JYK2 in response to different substrates.

Abstract

Characterization of lipid-degrading microorganisms and understanding their metabolite production mechanisms are essential for enhancing biodegradation efficiency of lipid-rich wastewater. In this study, we isolated Burkholderia arboris strain JYK2, which demonstrated lipid degradation at 46.29 mg/(l • h) with lipase activity reaching 59.92 U/ml when lipid was provided as the sole carbon source. Experimental results revealed that strain JYK2 secretes lipase in media containing lipids and fatty acids but not in glycerol-containing media, a phenomenon likely attributable to quorum sensing mechanisms. Furthermore, extracellular polymeric substances (EPS) were produced in the presence of lipids and fatty acids. Compositional analysis showed that EPS primarily consisted of proteins (approximately 50%) and polysaccharides (approximately 25%). This protein-rich characteristic conferred high hydrophobicity to the EPS, contributing to its lipase adsorption capacity as verified in this study. Additionally, biosurfactant activity was detected in the EPS produced by JYK2. These functions collectively enhance substrate utilization by microorganisms and promote lipid biodegradation. However, minimal EPS production was observed at low fatty acid concentrations, suggesting that the EPS production mechanism cannot be solely attributed to quorum sensing. This study provides insights into the interactions between lipid-degrading bacteria, lipase production, and EPS functionality, which are crucial for optimizing biological treatment of lipid-rich wastewater.