关键词: asymmetric reduction, 5-bistrifluoromethyl acetophenone, 5-bistrifluoromethylphenyl ethanol, immobilized cell, aqueous-organic solvent biphasic system

Abstract: Asymmetric reduction of 3,5-bistrifluoromethyl acetophenone to produce (S)-3,5-bistrifluoromethylphenyl ethanol was successfully carried out with sodium alginate immobilized Saccharomyces rhodotorula cells in an aqueous-organic solvent biphasic system. The possible influential factors were examined thoroughly according to their effects on conversion rate and e.e of the product. Organic solvents were rated by their biocompatibility and conversion potential. The immobilized cells [125 mg/mL in 20 mmol/L Tris-HCl buffer and 5%(j) octane at pH 8] showed the best conversion with a substrate concentration of 1.42 g/L at 30℃ with glucose as co-substrate for cofactor regeneration. Sequential 8-batch process was carried out with immobilized cells with a slow decrease in conversion and e.e. The immobilized cells showed stable catalytic activity with 50% reserved activity and are superior especially in reusability in comparison with resting cells.

Key words: asymmetric reduction, 5-bistrifluoromethyl acetophenone, 5-bistrifluoromethylphenyl ethanol, immobilized cell, aqueous-organic solvent biphasic system