Hydrocarbon degradation by a new Pseudomonas sp., strain RW-II, with polycationic surfactant to modify the cell hydrophobicity

Abstract

Pseudomonas putida RW-II isolated from petroleum refinery wastewater was tested for hydrocarbon degradation potential in the presence of polycationic surfactant, cetyl trimethylammonium bromide (CTAB). The effects of CTAB on growth profile, cell surface hydrophobicity, cell adhesion, zeta potential and hydrocarbon biodegradation were investigated. The addition of CTAB had a significant effect on the growth profile of RW-II and the growth was increased 1.11 times in hexadecane containing medium. In the presence of CTAB, the growth of Pseudomonas putida RW-II increased about 14.4%. The zeta potential of Pseudomonas putida RW-II decreased significantly when CTAB was added to the medium. The addition of CTAB not only decreased the zeta potential of surface, but also significantly increased the hydrophobicity of the cell surface. The degradation rate of hexadecane, anthracene and naphthalene was observed as 64.8%, 46% and 56% at the end of 120 h, respectively. Biodegradation of hexadecane, anthracene and naphthalene was enhanced 1.16, 1.15 and 1.08 times at 40 mg/L CTAB addition, respectively. The increase in biodegradation resulted from improved interaction between the hydrocarbon and microorganism derived from the increased adhesion. Thus, the use of CTAB has been proposed to be a valuable effect to enhance the biodegradation of hydrocarbons.