Biocatalysis of Biofuel Cells: Exploring the Intrinsic Bioelectrochemistry

Biofuel cells are potential multifaceted solutions to a myriad of environmental concerns of pollution, waste management, and resource depletion. Along with serving as alternative green energy sources, biofuel cells can simultaneously be used for wastewater treatment, bioremediation, and producing valuable by-products, viz., biohydrogen (Bio-H2). The underlying mechanism of energy production in biofuel cells lies in the catabolism of complex substrates by biocatalysts through fermentation or redox reactions with the subsequent release of electrons as by-products. The power-generating capacity of biofuel cells is dependent not only upon the biofuel system (anode-cathode materials, configuration of the cell), but equally upon the reactions involved in breaking down the substrates to produce electrons along with the electron transfer mechanisms. Despite the complex biochemical and electron pathways involved in electricity generation in biofuel cells, the same property proves biofuel cells to be advantageous over typical chemical fuel cells—a versatile range of substrates can be used for generating electricity. Also, due to the usage of biocatalysts in biofuel cells, the conditions required for electricity generation are milder as compared to typical chemical fuel cells. This chapter explores the types and various biochemical pathways of biocatalysts used in biofuel cells, electron transfer mechanisms, as well as anodic and cathodic reactions, with emphasis on recent advances and future prospects towards improving the performance of biofuel cell biocatalysts.