title: [Construction and evaluation of an engineered bacterial strain for producing lipopeptide under anoxic conditions].
abstract: Biosurfactant-facilitated oil recovery is one of the most important aspects of microbial enhanced oil recovery (MEOR). However, the biosurfactant production by biosurfactant-producing microorganisms, most of which are aerobes, is severely suppressed due to the in-situ anoxic conditions within oil reservoirs. In this research, we successfully engineered a strain JD-3, which could grow rapidly and produce lipopeptide under anoxic conditions, by protoplast confusion using a Bacillus amyloliquefaciens strain BQ-2 which produces biosurfactant aerobically, and a facultative anaerobic Pseudomonas stutzeri strain DQ-1 as parent strains. The alignment of 16S rDNA sequence (99% similarity) and comparisons of cell colony morphology showed that fusant JD-3 was closer to the parental strain B. amyloliquefaciens BQ-2. The surface tension of culture broth of fusant JD-3, after 36-hour cultivation under anaerobic conditions, decreased from initially 63.0 to 32.5 mN · m(-1). The results of thin layer chromatography and infrared spectrum analysis demonstrated that the biosurfactant produced by JD-3 was lipopeptide. The surface-active lipopeptide had a low critical micelle concentration (CMC) of 90 mg · L(-1) and presented a good ability to emulsify various hydrocarbons such as crude oil, liquid paraffin, and kerosene. Strain JD-3 could utilize peptone as nitrogen source and sucrose, glucose, glycerin or other common organics as carbon sources for anaerobic lipopeptide synthesis. The subculture of fusant JD-3 showed a stable lipopeptide-producing ability even after ten serial passages. All these results indicated that fusant JD-3 holds a great potential to microbially enhance oil recovery under anoxic conditions.
authors.forename: Xiao-long
authors.initials: XL
authors.lastname: Liang
authors.forename: Feng
authors.initials: F
authors.lastname: Zhao
authors.forename: Rong-jiu
authors.initials: RJ
authors.lastname: Shi
authors.forename: Yun-he
authors.initials: YH
authors.lastname: Ban
authors.forename: Ji-dong
authors.initials: JD
authors.lastname: Zhou
authors.forename: Si-qin
authors.initials: SQ
authors.lastname: Han
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D001407:Bacillus / Q000235:genetics / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002244:Carbon / Q000378:metabolism; D006838:Hydrocarbons / Q000378:metabolism; D055666:Lipopeptides / Q000096:biosynthesis*; D009584:Nitrogen / Q000378:metabolism; D030781:Organisms, Genetically Modified; D010578:Petroleum / Q000378:metabolism; D013500:Surface Tension; D013501:Surface-Active Agents / Q000378:metabolism*
chemical_list: D006838:Hydrocarbons; D055666:Lipopeptides; D010578:Petroleum; D013501:Surface-Active Agents; D002244:Carbon; D009584:Nitrogen