Enhancement of ethyl (S)-4-chloro-3-hydroxybutanoate production at high substrate concentration by in situ resin adsorption.

•A carbonyl reductase was discovered to reduce COBE to (S)-CHBE with high activity.•A cofactor regeneration system was built by coexpressing two genes in E. coli.•The product (S)-CHBE was the main inhibitor for the reaction.•In situ adsorption of (S)-CHBE by resin HZ 814 was used to avoid this inhibition.•COBE at 3000mM was completely reduced to (S)-CHBE (>99% ee) within 8h.