title: Pseudomonas aeruginosa UG2 rhamnolipid biosurfactants: structural characterization and their use in removing hydrophobic compounds from soil.
abstract: The structure of two rhamnolipid biosurfactants produced by Pseudomonas aeruginosa UG2 was studied. Analyses by gas chromatography-mass spectrometry and nuclear magnetic resonance spectroscopy showed these two rhamnolipids to be alpha-L-rhamnopyranosyl-beta-hydroxydecanyol-beta-hydroxydecanoate and 2-O-alpha-L-rhamnopyranosyl-alpha-L-rhamnopyranosyl-beta-hydroxydecan oyl-beta- hydroxydecanoate. The ability of UG2 rhamnolipid biosurfactants to enhance removal of naphthalene, anthracene, phenanthrene, fluorene, 2,2',5,5'-tetrachlorobiphenyl, and 3,3',4,4',5,5'-hexachlorobiphenyl into the aqueous phase was affected by soil type, hydrocarbon equilibration time, and biosurfactant adsorption to soil. Partially purified UG2 biosurfactants at a concentration of 5 g/L removed approximately 10% more hydrocarbon from a sandy loam soil than slit loam soil. High levels of UG2 rhamnolipids adsorbed to soil. In 18% (w/v) soil slurries 74, 49, 38, and 20% of 0.5, 1, 2, and 5 g UG2 rhamnolipids/L, respectively, were bound to the soil phase. Sodium dodecyl sulphate recovered lower levels and Witconol SN70 higher levels of phenanthrene and 2,2',5,5'-tetrachlorobiphenyl than UG2 biosurfactants.
authors.affiliation: Department of Environmental Biology, University of Guelph, ON, Canada.
authors.forename: M I
authors.initials: MI
authors.lastname: Van Dyke
authors.forename: P
authors.initials: P
authors.lastname: Couture
authors.forename: M
authors.initials: M
authors.lastname: Brauer
authors.forename: H
authors.initials: H
authors.lastname: Lee
authors.forename: J T
authors.initials: JT
authors.lastname: Trevors
mesh_terms: D002240:Carbohydrate Sequence; D003651:Decanoates / Q000737:chemistry* / Q000302:isolation & purification; D004187:Disaccharides / Q000737:chemistry* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D011550:Pseudomonas aeruginosa / Q000737:chemistry*; D012210:Rhamnose / Q000031:analogs & derivatives* / Q000737:chemistry / Q000302:isolation & purification; D012989:Soil Pollutants; D013501:Surface-Active Agents / Q000737:chemistry*
chemical_list: D003651:Decanoates; D004187:Disaccharides; D012989:Soil Pollutants; D013501:Surface-Active Agents; C085734:rhamnopyranosyl-3-hydroxydecanoyl-3-hydroxydecanoate; C085735:2-O-rhamnopyranosyl-rhamnopyranosyl-3-hydroxyldecanoyl-3-hydroxydecanoate; D012210:Rhamnose