Recent Advances in ω-Transaminase-Mediated Biocatalysis for the Enantioselective Synthesis of Chiral Amines

Chiral amines are important components of 40-45% of small molecule pharmaceuticals and many other industrially important fine chemicals and agrochemicals. Recent advances in synthetic applications of omega-transaminases for the production of chiral amines are reviewed herein. Although a new pool of potential omega-transaminases is being continuously screened and characterized from various microbial strains, their industrial application is limited by factors such as disfavored reaction equilibrium, poor substrate scope, and product inhibition. We present a closer look at recent developments in overcoming these challenges by various reaction engineering approaches. Furthermore, protein engineering techniques, which play a crucial role in improving the substrate scope of these biocatalysts and their operational stability, are also presented. Last, the incorporation of omega-transaminases in multi-enzymatic cascades, which significantly improves their synthetic applicability in the synthesis of complex chemical compounds, is detailed. This analysis of recent advances shows that omega-transaminases will continue to provide an efficient alternative to conventional catalysis for the synthesis of enantiomerically pure amines.