Cytochrome P450 monooxygenases in whole-cell format: Application notes from a biotechnological perspective

Cytochrome P450 monooxygenases (CYPs) are versatile heme-containing enzymes found across a diverse range of organisms. They play essential roles in hydrocarbon degradation, fatty acid metabolism, hormone biosynthesis, and xenobiotic detoxification. Their remarkable catalytic potential makes them attractive for biotechnological applications, particularly in the production of fine chemicals, pharmaceuticals, and bioactive compounds. However, scaling up the use of purified CYPs presents significant challenges due to their reliance on specific electron transfer partners (e.g., ferredoxin reductase and ferredoxin), cosubstrates such as NAD(P)H, and the tendency of these enzymes to lose activity outside of their native cellular environment. These factors result in costly and inefficient processes when purified enzymes are used in isolation. Whole-cell biotransformation offers a promising alternative, where CYPs are produced and function within living microbial hosts, providing a natural source of electron transfer partners and cosubstrates. This approach simplifies the reaction setup, enhances enzyme stability, and circumvents the need for costly purified components, thus facilitating industrial-scale applications. Moreover, whole-cell systems can leverage genetic engineering to optimize gene expression, improve substrate specificity, and increase yields. By exploring CYPs in a whole-cell format, this chapter highlights the potential of these enzymes to become a sustainable, cost-effective solution for the synthesis of high-value compounds, paving the way for environmentally friendly biocatalytic processes in the chemical and pharmaceutical industries.