title: Bioconversion of ethyl 4-chloro-3-oxobutanoate by permeabilized fresh brewer's yeast cells in the presence of allyl bromide.
abstract: Ethyl(R)-4-chloro-3-hydroxybutanoate ((R)-CHBE) are obtained by cetyltrimetylammonium bromide (CTAB) permeabilized fresh brewer's yeast whole cells bioconversion of ethyl 4-chloro-3-oxobutanoate (COBE ) in the presence of allyl bromide. The results showed that the activities of alcohol dehydrogenase (ADH) and glucose-6-phosphate dehydrogenase (G6PDH) in CTAB permeabilized brewer's yeast cells increased 525 and 7.9-fold, respectively, compared with that in the nonpermeabilized cells and had high enantioselectivity to convert COBE to (R)-CHBE. As one of co-substrates, glucose-6-phosphate was preprepared using glucose phosphorylation by hexokinase-catalyzed of CTAB permeabilized brewer's yeast cells. In a two phase reaction system with n-butyl acetate as organic solvent and with 2-propanol and glucose-6-phosphate as co-substrates, the highest (R)-CHBE concentration of 447 mM was obtained with 110-130 g/l of the CTAB permeabilized cells at optimized pH, temperature, feeding rate and the shake speed of 125 r/min. The yield and enantiomeric excess (ee) of (R)-CHBE reached 99.5 and 99%, respectively, within 6 h.
authors.affiliation: Pharmaceutical School, Chongqing University of Medical Sciences, Chongqing, 400016, China. minganyu666@yahoo.com.cn
authors.forename: Ming-An
authors.initials: MA
authors.lastname: Yu
authors.forename: Yu-Meng
authors.initials: YM
authors.lastname: Wei
authors.forename: Ling
authors.initials: L
authors.lastname: Zhao
authors.forename: Lan
authors.initials: L
authors.lastname: Jiang
authors.forename: Xiao-bing
authors.initials: XB
authors.lastname: Zhu
authors.forename: Wei
authors.initials: W
authors.lastname: Qi
mesh_terms: D019840:2-Propanol / Q000378:metabolism; D000090:Acetoacetates / Q000378:metabolism*; D000426:Alcohol Dehydrogenase / Q000378:metabolism; D000498:Allyl Compounds / Q000378:metabolism*; D002463:Cell Membrane Permeability; D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000378:metabolism; D019298:Glucose-6-Phosphate / Q000378:metabolism; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism; D006593:Hexokinase / Q000378:metabolism; D007218:Industrial Microbiology / Q000379:methods; D009249:NADP / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000254:growth & development / Q000378:metabolism*
chemical_list: D000090:Acetoacetates; D000498:Allyl Compounds; D002593:Cetrimonium Compounds; D009249:NADP; D019298:Glucose-6-Phosphate; C111982:ethyl 4-chloro-3-oxobutanoate; D000426:Alcohol Dehydrogenase; D005954:Glucosephosphate Dehydrogenase; D006593:Hexokinase; C050431:allyl bromide; D019840:2-Propanol; D000077286:Cetrimonium