11 - Biological and fermentative production of hydrogen

Abstract

Hydrogen gas is an attractive alternative sustainable energy due to its high energy density and zero greenhouse gas emission after combustion. Biological production of hydrogen by bacteria or algae operates under mild conditions and does not rely on fossil fuels or electricity. This chapter focuses on discussing the principles of hydrogen production by biological processes, including dark fermentation, biophotolysis by both algae and cyanobacteria, photofermentation, microbial electrolysis cell (MEC), cell-free enzymatic systems, as well as metabolic engineering strategies to improve hydrogen production. Additionally, the authors compare the available techniques using the most representative production indicators such as rate and efficiency. Due to the vast heterogeneity in resources available around the world, there is no absolute judgment on which technique is superior to another. The most appropriate technique should always be chosen based on whether it fits the local circumstances.