title: Stabilization of water-in-oil emulsion by Rhodococcus opacus B-4 and its application to biotransformation.
abstract: Rhodococcus opacus B-4, which has recently been isolated as an organic solvent-tolerant bacterium, stabilized water-in-oil (w/o) emulsions by inhibition of droplet coalescence when the cells were dispersed in 90% (v/v) organic solvents. Confocal microscopy revealed that many bacterial cells assembled at the interface between oil and water droplets, though free cells were also detectable at the inside of water droplets. Bacterial cells in the w/o emulsion were capable of utilizing both a water-soluble (glucose) and an oil-soluble substrate (oleic acid) as an energy source. Availability of the w/o emulsion as an immobilized cell system in organic solvents was demonstrated using production of indigo from indole and production of o-cresol from toluene as model conversions. When glucose and oleic acid were simultaneously supplied as energy sources, the w/o emulsion culture of R. opacus B-4 produced indigo and o-cresol at levels of 0.217 and 2.12 mg ml(-1), respectively, by 12 h.
authors.affiliation: Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan. honda@bio.eng.osaka-u.ac.jp
authors.forename: Kohsuke
authors.initials: K
authors.lastname: Honda
authors.forename: Shiho
authors.initials: S
authors.lastname: Yamashita
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Nakagawa
authors.forename: Yuka
authors.initials: Y
authors.lastname: Sameshima
authors.forename: Takeshi
authors.initials: T
authors.lastname: Omasa
authors.forename: Junichi
authors.initials: J
authors.lastname: Kato
authors.forename: Hisao
authors.initials: H
authors.lastname: Ohtake
mesh_terms: D001711:Biotransformation; D004655:Emulsions / Q000032:analysis / Q000378:metabolism; D007211:Indoles / Q000378:metabolism; D009821:Oils / Q000032:analysis / Q000378:metabolism*; D019301:Oleic Acid / Q000378:metabolism; D012240:Rhodococcus / Q000166:cytology / Q000302:isolation & purification / Q000378:metabolism*; D012988:Soil Microbiology; D014867:Water / Q000032:analysis / Q000378:metabolism*
chemical_list: D004655:Emulsions; D007211:Indoles; D009821:Oils; D014867:Water; D019301:Oleic Acid; C030374:indole