Influence of Rhamnolipid on the Treatment of Diesel Oil Contaminated Wastewater

Abstract

The influence of rhamnolipid on the emulsification and the biodegradation of diesel oil contaminated wastewater were investigated in this paper. It was found that the addition of rhamnolipid influenced positively the emulsification and the biodegradation efficiency of diesel oil contaminated wastewater. And the effect of rhamnolipid on parameters of lipopolysachharide (LPS) release, cell surface hydrophobicity and cell growth of isolates A1 and A2 (both are gram negative stains) were conducted respectively in order to reveal the influence of rhamnolipid on the biodegradation of diesel oil contaminate wastewater. The results demonstrated that the addition of rhamnolipid caused the release of LPS from the outer membrane of both isolates A1 and A2. And the cell surface of both isolates A1 and A2 becomes more hydrophobic upon the addition of rhamnolipid. This contributed to the increased association of cells with hydrophobic substrate diesel oil resulting in increased biodegradation rate. Go with LPS release and increased hydrophobic of isolates A1 and A2 was the increase in the growth rate on the substrate of diesel oil. And the influence of rhamnolipid on LPS release was different for isolates A1 and A2 used in this study. Isolate A1 released more proportion of LPS than that of isolate A2 upon the addition of rhamnolipid with diesel oil wastewater as substrate.