Continuous Flow Synthesis of Chiral Amines in Organic Solvents: Immobilization of E. coli Cells Containing Both ω-Transaminase and PLP

Organic Letters 16(23), 6092-6095, DOI: 10.1021/ol502712v

E. coli cells containing overexpressed (R)-selective ω-transaminase and the cofactor PLP were immobilized on methacrylate beads suitable for continuous flow applications. The use of an organic solvent suppresses leaching of PLP from the cells; no additional cofactor was required after setting up the packed-bed reactor containing the biocatalyst (ω-TA-PLP). Non-natural ketone substrates were transformed in flow with excellent enantioselectivity (>99%ee). Features of this novel system include high-throughput (30−60 min residence time), clean production (no quench, workup, or purification required), high enzyme stability (the packedbed reactor can be continuously operated for 1−10 days), and excellent mass recovery.