Covalently immobilized Trp60Cys mutant of ω-transaminase from Chromobacterium violaceum for kinetic resolution of racemic amines in batch and continuous-flow modes

Covalent immobilization of an engineered omega-transaminase mutant Trp60Cys from Chromobacterium violaceum (CvTA(w60c)) was performed on bisepoxide-activated aminoalkyl resins. Activity of the various CvTA(w60c) preparations was evaluated in kinetic resolution of four racemic amines (rac-1a-d). The most active EA-G-CvTA(w60c) preparation (CvTA(w60c) attached to polymeric resin with ethylamine function activated with glycerol diglycidyl ether EA-G) could perform the kinetic resolution of racemic 4-phenylbutan-2-amine (rac-1a) over 49% conversion up to 19 consecutive reaction cycles or in media containing up to 50% v/v DMSO as cosolvent in batch mode reactions. The immobilization process of CvTA(w60c) onto the EA-G resin filled in stainless steel bioreactors was also tested in flow-through mode. Kinetic resolution of three racemic amines containing aromatic moieties (rac-1a-c) was performed in continuous-flow mode resulting in easy-to-separate mixture of the corresponding ketone (2a-c) and the non-converted (R)-amine in high enantiopurity (ee((R)-1a-c) >= 96%). (C) 2018 Elsevier B.V. All rights reserved.