The Influences of Tween60 and Rhamnolipid on the Bioremediation of n-Hexadecane

The influences of adding Tween60 and rhamnolipid on n-hexadecane biodegradation and cell surface characteristics such as cell surface hydrophobicity (CSH) and lipopolysaccharide (LPS) release for two strains of Pseudomonas and Sphingomonas were investigated. The results showed that the additions of Tween60 and rhamnolipid have different effects on the strains of Pseudomonas and Sphingomonas as these two strains degrade n-hexadecane by different modes. The addition of rhamnolipid has a positive influence on the biodegradation of n-hexadecane for both the strains of the Pseudomonas and Sphingomonas. While the addition of Tween60 showed inhibition on the n-hexadecane biodegradation for both the strains of the Pseudomonas and Sphingomona. It could found that the addition of rhamnolipid could enhance the LPS release and increase the CSH for both of two strains, which can cause the sell surface of two strains of Pseudomonas and Sphingomona to become more hydrophobic, so increase the direct contact between the bacteria cell to the hydrocarbons. For the strain of Pseudomonas, the addition of Tween60 has no evident influence on the LPS release and has slightly effect on CSH. And the addition of Tween60 changed the LPS release to the supernatant very slightly and decreased the CSH of strain Sphingomonas dramatically.