Recent progress and continuing challenges in bio-fuel cells. Part II: Microbial.

Recent key developments in microbial fuel cell technology are reviewed. Fuel sources, electron transfer mechanisms, anode materials and enhanced O(2) reduction are discussed in detail. A summary of recently developed microbial fuel cell systems, including performance measurements, is conveniently provided in tabular form. The current challenges involved in developing practical bio-fuel cell systems are described, with particular emphasis on a fundamental understanding of the reaction environment, the performance and stability requirements, modularity and scalability. This review is the second part of a review of bio-fuel cells. In Part 1 a general introduction to bio-fuel cells, including their operating principles and applications, was provided and enzymatic fuel cell technology was reviewed.