Bug juice: harvesting electricity with microorganisms
Channel: EFET
Date: 2022-06-29

#MFC #microbialfuelcell #미생물연료전지 #sokheejung #정석희

Lovley D. Bug juice: harvesting electricity with microorganisms. Nat Rev Microbiol 2006 Jul; 4: 497–508. https://doi.org/10.1038/nrmicro1442

Key Points:

Microbial fuel cells have the potential to convert a wide diversity of organic wastes and renewable biomass to electricity. Many applications for microbial fuel cells are envisioned but, to date, the most practical use is the sediment microbial fuel cell, which is designed to recover electricity from the organic matter in aquatic sediments to power electronic-monitoring devices.

In a microbial fuel cell, electrons derived from the microbial oxidation of organic matter are transferred to the anode under anaerobic conditions and travel through the device that is to be powered into the cathode, where they combine with oxygen to form water.

It has recently been discovered that some microorganisms can completely oxidize organic compounds to carbon dioxide, with an electrode serving as the sole electron acceptor, and can conserve energy from this form of respiration. The term electricigens has been coined to describe such microorganisms.

Electricigen-powered microbial fuel cells can covert organic compounds to electricity more efficiently than earlier versions of microbial fuel cells, and do not require electron-shuttling mediators, which add cost, often have poor stability and can be toxic to humans. Furthermore, as long as fuel is available, electricigens are self-sustaining, resulting in fuel cells with long term stability.

The slow rate of conversion of organic matter to electricity in the currently available microbial fuel cells limits their application. Understanding the mechanisms of electron transfer to electrodes might help in designing anode materials that will promote faster electron transfer.

It is unlikely that there has been any selective pressure on electricigens to produce electricity at high rates in natural environments. Therefore, there could be substantial potential for optimizing this process with genetic engineering or adaptive evolution.

The availability of the complete genome sequence of several electricigens, such as Geobacter and Rhodoferax species, and the ability to track gene expression in electricigens growing on anodes, coupled with available genetic tools, is beginning to provide insights into the mechanisms of electron transfer to anodes.

Electrodes can also serve as an electron donor for microbial respiration and this might have applications for the removal of contaminants, such as toxic metals, nitrate and chlorinated solvents from polluted waters.