Alcohol dehydrogenase ((R)-specific Parvibaculum lavamentivorans) immobilized on non-porous glass carriers with polyvinyl alcohol (PVA) was applied to the reduction of 1-phenylethanone in a gas-phase bioreactor. As a function of the amount of PVA added at enzyme immobilization, the enzyme activity showed a maximum at 10 mg/g-glass carriers that was 2-fold higher than that of the PVA-free system, while the enzyme stability remained almost constant. The reaction was optimized at a water activity in the feed gas phase of 0.9 and a reaction temperature of 303-313 K. The stereoselectivity of the immobilized enzyme was maintained a high level (enantiomeric excess of 99%) under all the experimental conditions.