Advances in approaches for promoting electricigenic respiration of electroactive microorganisms

Abstract:

Microbial electricigenic respiration is a microbial metabolism mode in which electroactive microorganisms (EAMs) degrade organics and then transfer the produced electrons to extracellular solid electrodes through the respiratory chain, while EAMs gain energy to support their own growth. Microbial electricigenic respiration has broad application prospects in renewable energy utilization and environmental remediation. How to improve the microbial electricigenic respiration performances of EAMs is at the heart of promotion of relevant techniques from lab-scale research to full-scale application, and the electron transfer between EAMs and extracellular solid electrodes plays a pivotal role in microbial electricigenic respiration. To date, there have been many reviews focusing on how to improve electrode materials, however, very few literatures summarize how to strengthen the electricigenic respiration capability of EAMs. In this review, we summarized the existing approaches for promoting the respiratory performances of EAMs from the following three aspects:the addition of chemical reagents for example surfactants and signal molecules, physical force application such as ultrasonic waves and magnetic field forces, and genetic modification for instance phenazine secretion-related gene overexpression and pilA gene heterogenous expression. Advantages and disadvantages of each method were introduced, mechanisms and effects were expatiated upon, and future research directions from the perspectives of the practical application and the mechanism research were proposed.