title: Hydrophobicity development, alkane oxidation, and crude-oil emulsification in a Rhodococcus species.
abstract: The relationship between the phenomena alkane oxidation, extreme hydrophobicity of the cell surface, and crude-oil emulsification in Rhodococcus sp. strain 094 was investigated. Compounds that induce the emulsifying ability simultaneously induced the cytochrome P450-containing alkane oxidizing system and the transition from low to high cell-surface hydrophobicity. Exposed to inducers of crude-oil emulsification, the cells developed a strong hydrophobic character during exponential growth, which was rapidly lost when entering stationary phase. The loss in hydrophobicity coincided in time with the crude-oil emulsification, indicating that the components responsible for the formation of cell-surface hydrophobicity act as excellent emulsion stabilisers only after release from the cells. Rhodococcus sp. strain 094 possessed three distinct levels of cell-surface hydrophobicity. One level of low hydrophobicity was characteristic of cells in late stationary phase and was independent of growth substrate. A second and more hydrophobic level was observed for cells in exponential phase grown on water-soluble substrates, while a third level, characterised by extreme cell hydrophobicity, was observed for cells in exponential phase cultivated on hydrophobic substrates such as hexadecane. The production of the oil-emulsifying agents seems to require external sources of nitrogen and phosphate.
authors.affiliation: Department of Biotechnology, Faculty of Chemistry and Biology, The Norwegian University of Science and Technology, Trondheim. Bredholt@chembio.ntnu.no
authors.forename: Harald
authors.initials: H
authors.lastname: Bredholt
authors.forename: Per
authors.initials: P
authors.lastname: Bruheim
authors.forename: Martin
authors.initials: M
authors.lastname: Potocky
authors.forename: Kjell
authors.initials: K
authors.lastname: Eimhjellen
mesh_terms: D000473:Alkanes / Q000378:metabolism*; D001422:Bacterial Adhesion; D001673:Biodegradation, Environmental; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D004655:Emulsions; D004785:Environmental Pollutants / Q000378:metabolism; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D010084:Oxidation-Reduction; D010578:Petroleum / Q000378:metabolism*; D012240:Rhodococcus / Q000378:metabolism* / Q000502:physiology; D012623:Seawater / Q000382:microbiology; D013499:Surface Properties
chemical_list: D000473:Alkanes; D004655:Emulsions; D004785:Environmental Pollutants; D010578:Petroleum; D003577:Cytochrome P-450 Enzyme System