title: Synthesis, characterization, and oil recovery application of biosurfactant produced by indigenous pseudomonas aeruginosa WJ-1 using waste vegetable oils.
abstract: A bacterial strain was isolated and cultured from the oil excavation areas in tropical zone in northern China. The biochemical characteristics and partial sequenced 16S rRNA gene of isolate, WJ-1, was identical to those of cultured representatives of the species Pseudomonas aeruginosa. This bacterium was able to produce a type of biosurfactant. Compositional analysis revealed that the extracted biosurfactant was composed of high percentage lipid (∼74%, w/w) and carbohydrate (∼20%, w/w) in addition to a minor fraction of protein (∼6%, w/w). The best production of 50.2 g/l was obtained when the cells were grown on minimal salt medium containing 6.0% (w/v) glucose and 0.75% (w/v) sodium nitrate supplemented with 0.1% (v/v) element solution at 37 °C and 180 rpm after 96 h. The optimum biosurfactant production pH value was found to be 6.0-8.0. The biosurfactant of WJ-1, with the critical micelle concentration of 0.014 g/L, could reduce surface tension to 24.5 mN/m and emulsified kerosene up to EI(24) ≈95. The results obtained from time course study indicated that the surface tension reduction and emulsification potential was increased in the same way to cell growth. However, maximum biosurfactant production occurred and established in the stationary growth phase (after 90 h). Thin layer chromatography, Fourier transform infrared spectrum, and mass spectrum analysis indicate the extracted biosurfactant was affiliated with rhamnolipid. The core holder flooding experiments demonstrated that the oil recovery efficiency of strain and its biosurfactant was 23.02% residual oil.
authors.affiliation: Institute of Porous Flow & Fluid Mechanics, Chinese Academy of Sciences, Langfang, China.
authors.forename: Wen-Jie
authors.initials: WJ
authors.lastname: Xia
authors.forename: Zhi-Bin
authors.initials: ZB
authors.lastname: Luo
authors.forename: Han-Ping
authors.initials: HP
authors.lastname: Dong
authors.forename: Li
authors.initials: L
authors.lastname: Yu
authors.forename: Qing-Feng
authors.initials: QF
authors.lastname: Cui
authors.forename: Yong-Qiang
authors.initials: YQ
authors.lastname: Bi
mesh_terms: D005110:Extracellular Space / Q000378:metabolism; D006017:Glycolipids / Q000737:chemistry* / Q000302:isolation & purification* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste; D008670:Metals / Q000737:chemistry; D008823:Micelles; D010938:Plant Oils / Q000737:chemistry* / Q000378:metabolism*; D011550:Pseudomonas aeruginosa / Q000166:cytology / Q000302:isolation & purification / Q000378:metabolism*; D054712:Salinity; D013501:Surface-Active Agents / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D013696:Temperature
chemical_list: D006017:Glycolipids; D007220:Industrial Waste; D008670:Metals; D008823:Micelles; D010938:Plant Oils; D013501:Surface-Active Agents; C418382:rhamnolipid