title: Engineered baker's yeast as whole-cell biocatalyst for one-pot stereo-selective conversion of amines to alcohols.
abstract: BACKGROUND
  One-pot multi-step biocatalysis is advantageous over step-by-step synthesis as it reduces the number of process operation units, leading to significant process intensification. Whole-cell biocatalysis with metabolically active cells is especially valuable since all enzymes can be co-expressed in the cell whose metabolism can be exploited for supply of co-substrates and co-factors.
  
  
  RESULTS
  In this study, a heterologous enzymatic system consisting of ω-transaminase and ketone reductase was introduced in Saccharomyces cerevisiae, and evaluated for one-pot stereo-selective conversion of amines to alcohols. The system was applied for simultaneous kinetic resolution of racemic 1-phenylethylamine to (R)-1-phenylethylamine and reduction of the ketone intermediate to (R)-1-phenylethanol. Glucose was used as sole co-substrate for both the supply of amine acceptor and the regeneration of NADPH in the reduction step.
  
  
  CONCLUSIONS
  The whole-cell biocatalyst was shown to sustain transaminase-reductase-catalyzed enantioselective conversion of amines to alcohols with glucose as co-substrate. The transamination catalyzed by recombinant vanillin aminotransferase from Capsicum chinense proved to be the rate-limiting step as a three-fold increase in transaminase gene copy number led to a two-fold increased conversion. The (R)-selective NADPH-dependent alcohol dehydrogenase from Lactobacillus kefir proved to be efficient in catalyzing the reduction of the acetophenone generated in the transamination reaction.
authors.affiliation: Division of Applied Microbiology, Department of Chemistry, Lund University, Lund, SE-22100, Sweden. nora.weber@tmb.lth.se.
authors.forename: Nora
authors.initials: N
authors.lastname: Weber
authors.affiliation: Division of Applied Microbiology, Department of Chemistry, Lund University, Lund, SE-22100, Sweden. marie-francoise.gorwa@tmb.lth.se.
authors.forename: Marie
authors.initials: M
authors.lastname: Gorwa-Grauslund
authors.affiliation: Division of Applied Microbiology, Department of Chemistry, Lund University, Lund, SE-22100, Sweden. magnus.carlquist@tmb.lth.se.
authors.forename: Magnus
authors.initials: M
authors.lastname: Carlquist
mesh_terms: D002212:Capsicum / Q000201:enzymology / Q000235:genetics*; D010084:Oxidation-Reduction; D010627:Phenethylamines / Q000378:metabolism*; D010626:Phenylethyl Alcohol / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D000637:Transaminases / Q000235:genetics / Q000378:metabolism
chemical_list: D010627:Phenethylamines; D010940:Plant Proteins; D000637:Transaminases; D010626:Phenylethyl Alcohol