Stereoselective synthesis of (1S,2S)-1-phenylpropane-1,2-diol by cell-free extract of Lactobacillus brevis

In this study Lactobacillus brevis cells were cultivated and then disrupted using various cell disruption methods to obtain maximal nicotinamide adenine dinucleotide phosphate (NADP(H))-dependent alcohol dehydrogenase (ADH) activity in cell-free extract. Evolutionary operation (EVOP) technique was used to find the optimal cell disruption method. The released ADH in cell-free extract was then used for biotransformation of (S)-2-hydroxypropiophenone ((S)-2-HPP) to (1S, 2S)-1-phenylpropane-1,2-diol ((1S, 2S)-1-PPD). Due to high coenzyme cost, the possibility of NADPH regeneration was considered by examining two substrate-coupled regeneration systems, and for that isopropanol and (R)-1-phenylethanol were used. The enzyme was kinetically characterized, and kinetics of all reactions were determined. Based on kinetic results, mathematical models were developed and were validated in batch reactor. Both regenerating systems successfully shifted the reaction in the desired direction; without coenzyme regeneration, obtained substrate equilibrium conversion was 27.5%, while with coenzyme regeneration by isopropanol oxidation was 99.0% and by (R)-1-phenylethanol was 70.1%.