Description:
AbstractCyclohexanone monooxygenase (CHMO), a member of the Baeyer–Villiger monooxygenase family, is a versatile biocatalyst that efficiently catalyzes the conversion of cyclic ketones to lactones. In this study, an Acidovorax‐derived CHMO gene was expressed in Pseudomonas taiwanensis VLB120. Upon purification, the enzyme was characterized in vitro and shown to feature a broad substrate spectrum and up to 100% conversion in 6 h. Furthermore, we determined and compared the cyclohexanone conversion kinetics for different CHMO‐biocatalyst formats, that is, isolated enzyme, suspended whole cells, and biofilms, the latter two based on recombinant CHMO‐containing P. taiwanensis VLB120. Biofilms showed less favorable values for KS (9.3‐fold higher) and kcat (4.8‐fold lower) compared with corresponding KM and kcat values of isolated CHMO, but a favorable KI for cyclohexanone (5.3‐fold higher). The unfavorable KS and kcat values are related to mass transfer‐ and possibly heterogeneity issues and deserve further investigation and engineering, to exploit the high potential of biofilms regarding process stability. Suspended cells showed only 1.8‐fold higher KS, but 1.3‐ and 4.2‐fold higher kcat and KI values than isolated CHMO. This together with the efficient NADPH regeneration via glucose metabolism makes this format highly promising from a kinetics perspective.