Production of chiral amines with ω-transaminase

Various chiral amines were produced using (S)-specific ω-transaminase from Vibrio fluvialis JS17 screened from soil microorganisms. The ω-transaminase shows broad substrate specificity and high enantioselectivity. Product and substrate inhibitions were the major obstacles to make the reaction successful. To reduce the inhibitions and to use high concentration of the substrates, three processes for kinetic resolutions, i.e. two-liquid-phase system, enzyme membrane reactor, and packed-bed reactor, were compared. A membrane contactor was used to extract inhibitory ketone for the last two processes. Using the reaction processes, kinetic resolutions of the chiral amines (100-500 mM) were successfully carried out with ee>95 % of (R)-amines. Asymmetric synthesis of (S)-amines using prochiral ketone was also attempted and whole cell reaction proved to be successful due to the efficient removal of the product inhibition by pyruvate. However, the asymmetric reaction rate is much lower than the resolution reaction rate.