title: The effect of ethanol on cell properties and steroid 1-en-dehydrogenation biotransformation of Arthrobacter simplex.
abstract: Resting cells of Arthrobacter simplex with 1-en-dehydrogenation ability were prepared and treated by ethanol at subinhibitory concentrations (4%-15%, v/v), then added into the ethanol-free system containing low concentration of cortisone acetate (1 g L(-1)) to produce prednisone acetate by C1,2 dehydrogenation reaction. Results showed that, within the range of ethanol concentration, the initial conversion rate was varied significantly with the concentration of ethanol and the maximum was obtained at 8% (v/v) ethanol, which was increased by 32.6% compared with the control. A series of cell features closely relevant to biotransformation efficiency were further analyzed. It indicated that ethanol acting on cell wall and membrane could be used as a mediator to enhance cell permeability, which facilitated the penetration of substrate across cell barrier within a short time, resulting in the elevated initial conversation rate. The observation of fatty acids composition suggested that the increased unsaturated fatty acids, especially cis-isomers, in the presence of ethanol led to the disorganization of the native arrangement of lipids and thus increased cell permeability. Our findings demonstrated that another facilitation of ethanol was to promote substrate transport into cells by permeabilization, which would provide the guidance in the practical application of organic solvents in steroid biotransformation.
authors.affiliation: Key Laboratory of Industrial Fermentation Microbiology (Tianjin University of Science and Technology), Ministry of Education, Tianjin Key Lab of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, People's Republic of China.
authors.forename: Jianmei
authors.initials: J
authors.lastname: Luo
authors.forename: Jing
authors.initials: J
authors.lastname: Ning
authors.forename: Yanxia
authors.initials: Y
authors.lastname: Wang
authors.forename: Yongxin
authors.initials: Y
authors.lastname: Cheng
authors.forename: Yu
authors.initials: Y
authors.lastname: Zheng
authors.forename: Yanbing
authors.initials: Y
authors.lastname: Shen
authors.forename: Min
authors.initials: M
authors.lastname: Wang
mesh_terms: D001173:Arthrobacter / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D001709:Biotechnology; D001711:Biotransformation; D002463:Cell Membrane Permeability / Q000187:drug effects; D003348:Cortisone / Q000031:analogs & derivatives* / Q000378:metabolism; D000431:Ethanol / Q000494:pharmacology*; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D010088:Oxidoreductases / Q000378:metabolism
chemical_list: D005231:Fatty Acids, Unsaturated; D000431:Ethanol; D010088:Oxidoreductases; D003348:Cortisone
keywords: Arthrobacter simplex; biotransformation; cell permeability; ethanol; unsaturated fatty acid