Show, K.-Y.K.-Y.ShowYan, Y.-G.Y.-G.YanDUU-JONG LEE2021-02-042021-02-042019Show, K.-Y.;Yan, Y.-G.;Lee, D.-J.https://www.scopus.com/inward/record.url?eid=2-s2.0-85081315831&partnerID=40&md5=75d4ad0ef7b445a58a9c46c7dbc8a82ahttps://scholars.lib.ntu.edu.tw/handle/123456789/547674Increasing research work is being done to develop biohydrogen as an energy carrier substitute for fossil fuels. Biohydrogen has the likelihood to replace existing hydrogen production derived from fossil fuels. Perceived to be a renewable biofuel, biohydrogen is a clean fuel which yields only water upon combustion. While bioethanol and biodiesel have been successfully applied in the energy sector, the development of biohydrogen is still immature. Recent advancement indicated that some experimental biohydrogen processes have shown good potential for actual applications. This chapter sets forth a review in the state-of-the-art biohydrogen research focusing on the biological pathways, feedstocks, and bioreactor systems. Economics, perspectives, and outlook of biohydrogen production are also outlined. © 2019 Elsevier Inc. All rights reserved.Anaerobic; Biohydrogen; Biophotolysis; Dark fermentation; Photo-fermentation[SDGs]SDG6[SDGs]SDG7[SDGs]SDG12book part10.1016/B978-0-12-816856-1.00028-22-s2.0-85081315831