Production of the biosurfactant serrawettin W1 by Serratia marcescens S-1 improves hydrocarbon degradation.

With the frequent occurrence of oil spills, the bioremediation of petroleum hydrocarbons pollution has attracted more and more attention. In this study, we investigated the biodegradation of crude oil by the biosurfactant-producing strain S-1. The strain was isolated from petroleum-contaminated soil and identified as Serratia marcescens according to partial 16S rDNA gene analysis. It was able to effectively degrade hydrocarbons with the concomitant production of biosurfactants at 20-30 °C, while there was no biosurfactant production and the degradation rate was lower at 37 °C. The biosurfactant was identified as serrawettin W1 by UPLC-ESI-MS, and was found to reduce the surface tension of water to 30 mN/m, with stable surface activity and emulsion activity at temperatures from 20 to 100 °C, pH of 2-10 and NaCl concentrations of 0-50 g/L. Serrawettin W1 significantly increased the cell surface hydrophobicity (CSH) and enhanced the bioavailability of hydrocarbon pollutants, which was conducive to the degradation of crude oil, including long-chain alkanes and aromatic hydrocarbons. Serratia marcescens S-1 has potential applications in bioremediation at low temperature.