Abstract: Microbial fuel cells (MFCs) are devices that can use bacterial metabolism to
produce an electrical current from a wide range organic substrates. Due to the promise of
sustainable energy production from organic wastes, research has intensified in this field in
the last few years. While holding great promise only a few marine sediment MFCs have
been used practically, providing current for low power devices. To further improve MFC
technology an understanding of the limitations and microbiology of these systems is
required. Some researchers are uncovering that the greatest value of MFC technology
may not be the production of electricity but the ability of electrode associated microbes
to degrade wastes and toxic chemicals. We conclude that for further development of
MFC applications, a greater focus on understanding the microbial processes in MFC
systems is required.