Whole-cell biocatalysis for epoxidation using the non-heme diiron monooxygenase system PmlABCDEF

Non-heme diiron-dependent monooxygenases are versatile oxidative enzymes that catalyze a wide range of oxy-functionalization reactions, including the conversion of CC bonds into epoxides. Despite their potential, their use as biocatalysts is limited due to challenges in expressing their multi-subunit structure in conventional hosts. Consequently, these enzymes exhibit relatively low activity in epoxidation reactions, significantly restricting their practical applications. Nevertheless, pairing appropriate enzymatic systems with carefully chosen expression vectors in suitable host organisms shows great promise. This chapter focuses on the PmlABCDEF monooxygenase system, expressed in Pseudomonas putida KT2440 and utilized as a whole-cell biocatalyst for epoxidation. The methodology details the construction of two distinct expression plasmids and their application in the preparative-scale bio-epoxidation reactions using two different substrate types. This approach is versatile and can be readily adapted for a broad range of epoxide production and other oxygenation-based transformations.