Bioreduction and disproportionation of cyclohex-2-enone catalyzed by ene-reductase OYE-1 in ‘micro-aqueous’ organic solvents
The bioreduction and disproportionation of cyclohex-2-enone catalyzed by Old Yellow Enzyme 1 was investigated in presence of organic (co)solvents. Whereas the NADH-dependent bioreduction activity strongly decreased at elevated co-solvent concentrations due to the insolubility of the nicotinamide-cofactor, the NADH-free disproportionation was significantly improved in water-immiscible organic co-solvents at 90 % (v/v) with near-quantitative conversion. This positive effect was attributed to removal of the inhibiting co-product, phenol, from the enzyme’s active site. The best co-solvents show high lipophilicity (logP) and a high potential to solubilize phenol (Kphenol). As a predictive parameter, the ratio of logP/Kphenol should be preferably ≥100.
KeywordsBioreduction Cyclohexanone Cyclohex-2-enone Disproportionation Ene-reductase Micro-aqueous systems Old yellow enzyme Phenol
Financial support by the Austrian BMWFJ, BMVIT, SFG, Standortagentur Tirol and ZIT through the Austrian FFG-COMET-funding program and the Austrian Science Fund (FWF, Vienna, project P22722) is gratefully acknowledged.