Microbial oil degradation in the environment and response strategies during oil spill scenarios are interdisciplinary research topics of broad significance.Surfactants are routinely applied as an emergency response to oil spills with the goal of enhancing the dissolution ofoil into water,which is assumed to stimulate microbially mediated oil biodegradation.Recently,biosurfactants which are produced by microorganisms have gained increasing interest due to their wide functional diversity,lower toxicities and higher biodegradability,compared to their chemically-synthesized counterparts.However,recent studies revealed contrasting findings and critical knowledge gaps regarding the impacts ofbiosurfactants on microbial community structure.In laboratory experiments,we simulated environmental conditions comparable to oil spill on the surface seawater collected from Shenzhen Bay.The microbial growth and activity was stimulated by oil,biosurfactant.The natural oil degrading bacteria Pseudomonas and Rhodobacteraceae were observed obviously stimulated by the addition of biosurfactants.Biosurfactant might enhance hydrocarbon oxidation rate.The upcoming GC-MS data could reveal biosurfactant impacts on oil biodegradation potentials.The presence of biosurfactants also significantly increased the microbial community composition through selection for potential biosurfactants degrading bacteria Rhodococcus and Algoriphagus.These results contribute to an increased understanding of the impact of biosurfactant on marine microorganism communities before commercial release into the environment.