Cytochrome P450 enzyme-based biotransformation of pharmaceuticals and personal care products (PPCPs) by microalgae in the aquatic environment

Pharmaceuticals and personal care products (PPCPs) are often found in aquatic environments. Microalgae-based bioremediation is cost-effective and ecologically friendly. The transformation of PPCPs by microalgal cytochrome P450 enzymes (P450s) may critically impact bioremediation efficacy; however, studies focusing on the detailed PPCP biodegradation pathways in microalgae involving P450s are scarce. This review provides a concise summary of microalgal P450 diversity and the critical factors affecting their expression and function, focusing on the biotransformation of PPCPs. Notably, most studies on PPCPs have focused on laboratory experiments and environmental investigations, while only a few have reported on the removal of PPCPs using density functional theory. Versatile techniques have been recommended to meet the needs of different applications, involving protein engineering of P450s and redox partners, substrate engineering, cofactor regeneration, and P450s-related metabolic engineering. In addition, current challenges (such as complexity, poor stability, and low activity) and perspectives for P450-based PPCP biodegradation are also highlighted. This review aims to provide theoretical knowledge towards the understanding of microalgal P450-based biotransformation of PPCPs to facilitate future implementation of this remediation technology.