Electron transfer regulation-based biotechnology for emerging contaminants treatment

Wastewater effluent has been recognized as one of the main sources of emerging contaminants (ECs) entering into the aquatic environment. Even though their presence is in relatively low concentrations, ECs have the potential for acute or chronic toxicity that affects ecology safety and population health. Biotransformation is an important contributor to the fate of ECs in wastewater treatment plants. However, the traditional biological processes encounter great challenges for ECs removal due to the limited availability of electrons. This chapter provides a comprehensive summary of various regulation approaches aimed at enhancing biotransformation efficiency based on electron transfer mechanisms. Conductive materials, such as carbon/metal materials improve the electron transfer by acting as electron conduits or shuttles. The utilization of limited oxygen as an electron acceptor enhances the metabolic energy. Solid electrodes can be used as either external electron donor or acceptor, further supplying extra electron transfer pathways. Other effects of these strategies including changes of metabolic activity and microbial interactions are also important factors for the regulation of ECs biotransformation. Promising integrated strategies, coupled with microbial mechanisms delineation using multiomics and process optimization driven by data science, would have substantial impacts on the controlling of ECs fate in the electron transfer-based regulation biological systems.