New energy sources: the enzymatic biofuel cell

The continuous search for alternative energy sources, imposed by economic and environmental concerns, has motivated investigations into clean and efficient alternatives for energy production. Studies have shown that fuel cells are a potentially efficient strategy for energy conversion. Biofuel cells constitute a subclass of fuel cells with promising application in low-power devices (generally in the order of micro to milli watts). Instead of metallic catalysts, biological power sources employ biological molecules such as enzymes, organelles, or microorganisms to convert chemical energy into electricity. Biofuel cells offer several advantages over traditional batteries, including the use of renewable and non-toxic components, reaction selectivity, fuel flexibility, and ability to operate at lower temperatures and near neutral pH. Indeed, recent papers have demonstrated the promising characteristics of these devices; however, some challenges remains to be faced despite the several advances in this area. This review aims to provide the readers of the Journal of the Brazilian Chemical Society with an overview of enzymatic biofuel cells, their development since its first description in 1964, and the most recent outcomes. The latest papers in this field (including implantable technology) and an outlook for future research in this area are also presented.