An effective biosurfactant-producer and hydrocarbon degrading bacterial strain, Rhodococcus sp. HL-6 was isolated from Xinjiang oil field using diesel oil as sole source of carbon. The produced biosurfactant (BS) had the ability to decrease the surface tension (ST) of distilled water from 72.5 to 30.7 mN/m, with the critical micelle concentration (CMC) of 40 mg/L. Subsequently, the BS characterization was made by thin-layer chromatography (TLC) and infrared spectra analysis. The stability was determined by EI24 value measurement over a certain pH (4-10), temperature (4-100 degrees C) and salt concentration (0-5% w/v) ranges. The glycolipid quality of the BS was further determined. To deduce the role of solid bioagent in diesel oil degradation, a comparison of solid bioagent and liquid bioagent was investigated. The study suggested application of the HL-6 BS as an appropriate candidate for bioremediation of crude oil contaminants. To our knowledge, this is the first report showing detailedly introduce the surface properties and biological activity of glycolipid biosurfactant producing strain (Rhodococcus sp.).
