Biological Hydrogen Production

Sustainable energy production, such as biofuels, is a critical global challenge, and exploring alternative energy sources has become increasingly valuable in recent years. Among various renewable fuels, hydrogen ( H 2 ) production proves beneficial in terms of high energy. The biological H 2 production (BHP) approaches offer a sustainable and environmentally friendly solution for H 2 production, providing multiple benefits, including reducing greenhouse gas (GHG) emissions, promoting sustainable development, increasing energy independence, diversifying energy sources, and enhancing rural development. One promising avenue is the BHP from renewable sources, such as biomass or biowastes, as suitable alternative feedstocks over costly purified sugars. The selection of defined mixed cultures as H 2 producers can be beneficial over pure or enriched cultures to enhance H 2 yields with their diverse properties, such as their broad substrate utilization potential and better operational stability, and promote non-sterile biotransformation. Further, integrating the BHP with other biofuels or value-added products such as polyhydroxyalkanoates can be more desirable for achieving the complete valorization of biowastes, a better bioprocess economy, and GHG mitigation. This book chapter presents comprehensive detail on BHP through dark-fermentative strategies, and further, its integration into other bioprocesses is discussed with future perspectives.