Biosurfactant production and hydrocarbon-degradation by halotolerant and thermotolerant Pseudomonas sp

• Published in: World journal of microbiology & biotechnology 2008-07, Vol.24 (7), p.1047-1057
• Main Authors: Kumar, Manoj, León, Vladimir, De Sisto Materano, Angela, Ilzins, Olaf A, Luis, Luis
• Format: Article
• Language: English
• Subjects: Applied Microbiology; Bacteria; Biochemical analysis; Biochemistry; Biodegradation; Biological and medical sciences; Biomedical and Life Sciences; Bioremediation; Biotechnology; Carbon; Carbon sources; Crude oil; Environmental Engineering/Biotechnology; Fundamental and applied biological sciences. Psychology; Hydrocarbons; Life Sciences; Microbiology; Microorganisms; Naphthalene; Oil pollution; Original Paper; Petroleum industry; Polycyclic aromatic hydrocarbons; Pseudomonas aeruginosa; R&D; Research & development; Salinity; Soil contamination; Studies; Surface tension; Surfactants; Temperature; Toluene
• ISSN: 0959-3993; 1573-0972
• DOI: 10.1007/s11274-007-9574-5

A hydrocarbon degrading and biosurfactant producing, strain DHT2, was isolated from oil-contaminated soil. The organism grew and produced biosurfactant when cultured in variety of substrates at salinities up to 6 g l⁻¹ and temperatures up to 45°C. It was capable of utilizing crude oil, fuels, alkanes and PAHs as carbon source across the wide range of temperature (30-45°C) and salinity (0-6%). Over the range evaluated, the salinity and temperature did not influence the degradation of hydrocarbon and biosurfactant productions. Isolate DHT2 was identified as Pseudomonas aeruginosa by analysis of 16S rRNA sequences (100% homology) and biochemical analysis. PCR and DNA hybridization studies revealed that enzymes involved in PAH metabolism were related to the naphthalene dioxygenase pathway. Observation of both tensio-active and emulsifying activities indicated that biosurfactants were produced by DHT2 during growth on both, water miscible and immiscible substrates, including PAH. The biosurfactants lowered the surface tension of medium from 54.9 to 30.2 dN/cm and formed a stable emulsion. The biosurfactant produced by the organism emulsified a range of hydrocarbons with hexadecane as best substrate and toluene was the poorest. These findings further indicate that the isolate could be useful for bioremediation and bio-refining application in petroleum industry.