Synthesis of S-licarbazepine by asymmetric reduction of oxcarbazepine with Saccharomyces cerevisiae CGMCC No. 2266

S-licarbazepine was synthesized by asymmetric reduction of oxcarbazepine with CGMCC No. 2266. The optimum batch reduction conditions were found to consist of a reaction time of 36 h, temperature of 30 °C, and initial pH value of 7.0. The optimum concentration of the glucose co-substrate was found to be 0.3 mol L−1. The addition of glucose contributed to in situ regeneration of NADPH in cells and improved conversion. Conversion increased with the addition of more biomass and with a decrease in the initial concentration of substrate. Within the membrane reactor, a continuous reduction process was used to improve production efficiency and reduce the inhibition of high-concentration substrate upon reduction. The optimum flux was found to be 20 ml h−1. S-licarbazepine yield was 3.7678 mmol L−1 d−1 in continuous reduction over four days. The enantiometric excess of S-licarbazepine was 100% for both batch and continuous reduction processes.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► S-licarbazepine was synthesized by batch and continuous reduction of oxcarbazepine with CGMCC No. 2266. ► The enantiometric excess of S-LC was 100% in batch and continuous reduction process. ► Addition of glucose contributed to in situ regeneration of NADPH in cells and improvement of conversion. ► Continuous reduction process in membrane reactor was used for improvement the production efficiency. ► S-licarbazepine yield was 3.7678 mmol L−1 d−1 in continuous reduction over four days.