Aims: To isolate a biosurfactant (BS)-producing bacterium, to characterize the BS properties and to evaluate its ability to enhance pesticide solubilization for further application in environmental remediation.
Methods and results: Five BS-producing bacteria were isolated from fuel oil-contaminated soil. Among them, Burkholderia cenocepacia BSP3 exhibited the highest emulsification index and was chosen for further study. Glucose-containing medium supplemented with nitrate or sunflower seed oil provided suitable conditions for growth and BS production. The BS was identified as a glucolipid, having a critical micelle concentration (CMC) of 316 mg l(-1). It could lower the surface tension of deionized water to 25 +/- 0.2 mN m(-1) and exhibited good emulsion stability. Finally, the application of the BS to facilitate pesticide solubilization demonstrated that this BS at the concentration below and above its CMC could enhance the apparent water solubility of three pesticides, i.e. methyl parathion, ethyl parathion and trifluralin.
Conclusions: Burkholderia cenocepacia BSP3 is a BS-producing bacterium isolated from oil-contaminated soil. The BS was identified as a glucolipid having a molecular mass of 550.4 g mol(-1). An apparent yield of the BS was 6.5 +/- 0.7 g l(-1). This glucolipid-type BS noticeably enhanced pesticide solubilization suggesting its role in environmental remediation.
Significance and impact of the study: A glucolipid type BS normally found in marine micro-organisms was isolated from a soil-bacterium. Due to its surface active properties and good performance in enhancement of pesticide solubilization, it could be used as a solubilizing agent for environmental remediation and synergistic treatment with bioremediation of pesticide-contaminated soil.