Purification and characterization of biosurfactant produced by Bacillus licheniformis Y-1 and its application in remediation of petroleum contaminated soil

•A biosurfactant produced by a petroleum degrading bacteria strain Bacillus licheniformis Y-1 was isolated and purified.•This biosurfactant was determined to have excellent emulsifying activity.•By using FT-IR and 1H NMR, the structure of this biosurfactant was determined to be a cyclic lipopeptide.•Through the addition of this biosurfactant, the effect of petroleum contaminated soil remediation by fungi got a significant improvement.

In our previous research, a petroleum degrading bacteria strain Bacillus licheniformis Y-1 was obtained in Dagang Oilfield which had the capability of producing biosurfactant. This biosurfactant was isolated and purified in this work. The biosurfactant produced by strain Y-1 had the capability to decrease the surface tension of water from 74.66 to 27.26 mN/m, with the critical micelle concentration (CMC) of 40 mg/L. The biosurfactant performed not only excellent stabilities against pH, temperature and salinity, but also great emulsifying activities to different kinds of oil, especially the crude oil. According to the results of FT-IR spectrum and 1H NMR spectrum detection, the surfactant was determined to be a cyclic lipopeptide. Furthermore, through the addition of surfactant, the effect of petroleum contaminated soil remediation by fungi got a significant improvement.