Light-driven bioprocesses

Enzyme catalysis and photocatalysis are two research areas that have become of major interest in organic synthesis. This is mainly because both represent attractive strategies for making chemical synthesis more efficient and sustainable. Because enzyme catalysis offers several inherent advantages, such as high substrate specificity, regio-, and stereoselectivity, and activity under environmentally benign reaction conditions, biocatalysts are increasingly being adopted by the pharmaceutical and chemical industries. In addition, photocatalysis has proven to be a powerful approach for accessing unique reactivities upon light irradiation and performing reactions with an extended substrate range under milder conditions compared to light-independent alternatives. It is therefore not surprising that bio-and photocatalytic approaches are now often combined to exploit the exquisite selectivity of enzymes and the unique chemical transformations accessible to photocatalysis. In this chapter, we provide an overview of the wide variety of lightdriven bioprocesses, ranging from photochemical delivery of reducing equivalents to redox enzymes, photochemical cofactor regeneration, to direct photoactivation of enzymes. We also highlight the possibility of catalyzing non-natural reactions via photoinduced enzyme promiscuity and the combination of photo-and biocatalytic reactions used to create new synthetic methodologies.