title: Structural and physicochemical characterization of crude biosurfactant produced by Pseudomonas aeruginosa SP4 isolated from petroleum-contaminated soil.
abstract: Pseudomonas aeruginosa strain SP4, isolated from petroleum-contaminated soil in Thailand, was used to produce a biosurfactant from a nutrient broth with palm oil as the carbon source. The key components of the crude biosurfactant were fractionated by using HPLC-ELSD technique. With the use of ATR-FTIR spectroscopy, in combination with (1)H NMR and MS analyses, chemical structures of the fractionated components of the crude biosurfactant were identified as rhamnolipid species. When compared to synthetic surfactants, including Pluronic F-68, which is a triblock nonionic surfactant containing poly(ethylene oxide) and poly(propylene oxide), and sodium dodecyl sulfate, the crude biosurfactant showed comparable physicochemical properties, in terms of the surface activities. The crude biosurfactant reduced the surface tension of pure water to 29.0 mN/m with a critical micelle concentration of approximately 200 mg/l, and it exhibited good thermal and pH stability. The crude biosurfactant also formed stable water-in-oil microemulsions with crude oil and various types of vegetable oils, but not with short-chain hydrocarbons.
authors.affiliation: The Petroleum and Petrochemical College, Chulalongkorn University, Bangkok, Thailand.
authors.forename: Orathai
authors.initials: O
authors.lastname: Pornsunthorntawee
authors.forename: Panya
authors.initials: P
authors.lastname: Wongpanit
authors.forename: Sumaeth
authors.initials: S
authors.lastname: Chavadej
authors.forename: Masahiko
authors.initials: M
authors.lastname: Abe
authors.forename: Ratana
authors.initials: R
authors.lastname: Rujiravanit
mesh_terms: D001673:Biodegradation, Environmental; D001709:Biotechnology / Q000379:methods*; D004787:Environmental Pollution; D006838:Hydrocarbons / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D010578:Petroleum; D020442:Poloxamer / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D011409:Propylene Glycols / Q000737:chemistry; D011550:Pseudomonas aeruginosa / Q000378:metabolism*; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D012989:Soil Pollutants / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013500:Surface Tension; D013501:Surface-Active Agents / Q000737:chemistry*
chemical_list: D006838:Hydrocarbons; D010578:Petroleum; D011108:Polymers; D011409:Propylene Glycols; D012989:Soil Pollutants; D013501:Surface-Active Agents; D020442:Poloxamer; C012504:polypropylene glycol; D012967:Sodium Dodecyl Sulfate; D011092:Polyethylene Glycols