title: Biocatalytic anti-Prelog reduction of prochiral ketones with whole cells of Acetobacter pasteurianus GIM1.158.
abstract: BACKGROUND
  Enantiomerically pure alcohols are important building blocks for production of chiral pharmaceuticals, flavors, agrochemicals and functional materials and appropriate whole-cell biocatalysts offer a highly enantioselective, minimally polluting route to these valuable compounds. At present, most of these biocatalysts follow Prelog's rule, and thus the (S)-alcohols are usually obtained when the smaller substituent of the ketone has the lower CIP priority. Only a few anti-Prelog (R)-specific whole cell biocatalysts have been reported. In this paper, the biocatalytic anti-Prelog reduction of 2-octanone to (R)-2-octanol was successfully conducted with high enantioselectivity using whole cells of Acetobacter pasteurianus GIM1.158.
  
  
  RESULTS
  Compared with other microorganisms investigated, Acetobacter pasteurianus GIM1.158 was shown to be more effective for the reduction reaction, affording much higher yield, product enantiomeric excess (e.e.) and initial reaction rate. The optimal temperature, buffer pH, co-substrate and its concentration, substrate concentration, cell concentration and shaking rate were 35°C, 5.0, 500 mmol/L isopropanol, 40 mmol/L, 25 mg/mL and 120 r/min, respectively. Under the optimized conditions, the maximum yield and the product e.e. were 89.5% and >99.9%, respectively, in 70 minutes. Compared with the best available data in aqueous system (yield of 55%), the yield of (R)-2-octanol was greatly increased. Additionally, the efficient whole-cell biocatalytic process was feasible on a 200-mL preparative scale and the chemical yield increased to 95.0% with the product e.e. being >99.9%. Moreover, Acetobacter pasteurianus GIM1.158 cells were proved to be capable of catalyzing the anti-Prelog bioreduction of other prochiral carbonyl compounds with high efficiency.
  
  
  CONCLUSIONS
  Via an effective increase in the maximum yield and the product e.e. with Acetobacter pasteurianus GIM1.158 cells, these results open the way to use of whole cells of this microorganism for challenging enantioselective reduction reactions on laboratory and commercial scales.
authors.forename: Peng-Xuan
authors.initials: PX
authors.lastname: Du
authors.forename: Ping
authors.initials: P
authors.lastname: Wei
authors.affiliation: Laboratory of Applied Biocatalysis, South China University of Technology, Guangzhou 510640, China. wylou@scut.edu.cn.
authors.forename: Wen-Yong
authors.initials: WY
authors.lastname: Lou
authors.forename: Min-Hua
authors.initials: MH
authors.lastname: Zong
mesh_terms: D000091:Acetobacter / Q000378:metabolism*; D061249:Batch Cell Culture Techniques; D055162:Biocatalysis; D006863:Hydrogen-Ion Concentration; D007659:Ketones / Q000737:chemistry / Q000378:metabolism*; D000442:Octanols / Q000737:chemistry / Q000378:metabolism; D010084:Oxidation-Reduction; D013237:Stereoisomerism; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D007659:Ketones; D000442:Octanols; C067943:2-octanol; C037075:2-octanone