An organic-single-phase CSTR process for the chemo-enzymatic epoxidation of α-pinene enables high selectivity and productivity

The aim of this work was to develop a new process strategy for the in-situ lipase-mediated synthesis of alpha-pinene oxide. To minimize the limitation of enzyme deactivation encountered in these reaction cascades, an organic-single-phase continuous stirred tank reactor (ospCSTR) process was developed. Considering the numerous degrees of freedom of this continuous multistep reaction which due to enzyme deactivation additionally has no steady-state, the process development is a challenging task. Therefore, the influence of operating parameters on the efficiency was studied in detail. Due to the avoidance of harsh conditions, at optimized parameters a-pinene oxide was produced selectively (95%), and with high space-time yields (880 gpo L-1 d(-1)). The catalytic productivity (118 gpo g(-1) calB) was significantly higher than previously reported. To counterbalance the reduced but still present deactivation, the opsCSTR was enhanced with intermittent enzyme dosing which, for the first time, enabled long-term operation, high catalytic productivity, and high space-time yield. With the ospCSTR augmented by enzyme dosing, we report an economical process for a chemo-enzymatic epoxidation of sensitive terpenes like e.g., alpha-pinene. 2017 Elsevier B.V. All rights reserved.