title: Isolation and partial characterization of a biosurfactant mixture produced by Sphingobacterium sp. isolated from soil.
abstract: Strain 6.2S, isolated from soil and identified as a Sphingobacterium sp., is the first strain in this genus to be reported as a biosurfactant producer, being able to reduce the surface tension of its culture supernatant to 32 mN/m. In this work, biosurfactants from the culture supernatant were purified and partially characterized. The crude extract (10 g/L) was very effective in reducing surface tension (22 mN/m). Thin layer chromatography (TLC) indicated that a mixture of various biosurfactants was present in the 6.2S crude extract. After purification, Fraction A, a phospholipid mixture, reduced surface tension to 33 mN/m. Fraction B was a mixture of lipopetides and at least one glycolipid. The surface tension-concentration curve showed two plateaux, the first of which can be attributed to a critical aggregation concentration of the biosurfactant with a protein (2.7 g/L) and the second to the true cmc in water (6.3g/L).
authors.affiliation: Faculty of Pharmacy, University Barcelona, Barcelona, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Burgos-Díaz
authors.forename: R
authors.initials: R
authors.lastname: Pons
authors.forename: M J
authors.initials: MJ
authors.lastname: Espuny
authors.forename: F J
authors.initials: FJ
authors.lastname: Aranda
authors.forename: J A
authors.initials: JA
authors.lastname: Teruel
authors.forename: A
authors.initials: A
authors.lastname: Manresa
authors.forename: A
authors.initials: A
authors.lastname: Ortiz
authors.forename: A M
authors.initials: AM
authors.lastname: Marqués
mesh_terms: D002855:Chromatography, Thin Layer; D006017:Glycolipids / Q000302:isolation & purification; D055666:Lipopeptides / Q000302:isolation & purification; D010743:Phospholipids / Q000302:isolation & purification; D012988:Soil Microbiology; D045249:Sphingobacterium / Q000737:chemistry*; D013500:Surface Tension; D013501:Surface-Active Agents / Q000302:isolation & purification*
chemical_list: D006017:Glycolipids; D055666:Lipopeptides; D010743:Phospholipids; D013501:Surface-Active Agents