Tailored sol–gel immobilized lipase preparates for the enzymatic kinetic resolution of heteroaromatic alcohols in batch and continuous flow systems

Abstract

Tailored immobilized lipases from Candida antarctica B and Pseudomonas fluorescens, with improved thermal and operational stability, were prepared through fine tuning of the structure of the sol–gel matrix, using various binary or ternary precursor mixtures for the EKR of various chiral heteroaromatic secondary alcohols with benzofuran, benzo[b]thiophen, phenothiazine and 2-phenylthiazol moieties. The operational stability in batch process was studied for five selected systems by performing reuse experiments, using the conversion, enantiomeric excesses and enantiomeric ratio as parameters, demonstrating the dependence of the sol–gel lipase preparate performance on the structure of both biocatalyst and substrate. The resolution of the benzofuranic substrates with the best performing biocatalysts was studied in continuous-flow mode, using the productivity as a criterion. The specific reaction rates under continuous-flow operation (r_flow) were higher than those obtained in batch mode (r_batch) in both cases, sustaining its usefulness for further process development.