Dark fermentation is microbial conversion of organic substrates into hydrogen and other fermentation products without a requirement for light energy. Anaerobic substrate breakdown generates reducing equivalents that can be transferred to hydrogen-producing enzymes [1]. The culture may contain multiple microbial populations whose metabolic activities distribute carbon and electrons among hydrogen, organic acids, and other products [2]. Complex feedstocks must first yield compounds accessible to the fermenting organisms, connecting substrate hydrolysis to downstream hydrogen formation [3]. Competing metabolic branches consume the same intermediates and reducing equivalents, so changes in pathway flux alter the product distribution [4]. Hydrogen leaves the liquid phase through gas transfer, while soluble fermentation products remain in the medium. These linked biological and transport processes establish the evolving composition of the fermenting culture [5].
- fermentative hydrogen
- anaerobic metabolism
- organic substrates
- reducing equivalents
References
- Patrick C. Hallenbeck; Dipankar Ghosh; Advances in Fermentative Biohydrogen Production: the Way Forward?. Trends Biotechnol. 2009, 27, 287-297, 10.1016/j.tibtech.2009.02.004.
- Lea Cabrol; Antonella Marone; Estela Tapia-Venegas; Jean-Philippe Steyer; Gonzalo Ruiz-Filippi; Eric Trably; Microbial Ecology of Fermentative Hydrogen Producing Bioprocesses: Useful Insights for Driving the Ecosystem Function. FEMS Microbiol. Rev. 2017, 41, 158-181, 10.1093/femsre/fuw043.
- Nanqi Ren; Aijie Wang; Guangli Cao; Jifei Xu; Lingfang Gao; Bioconversion of Lignocellulosic Biomass to Hydrogen: Potential and Challenges. Biotechnol. Adv. 2009, 27, 1051-1060, 10.1016/j.biotechadv.2009.05.007.
- Guiqin Cai; Bo Jin; Paul Monis; Chris Saint; Metabolic Flux Network and Analysis of Fermentative Hydrogen Production. Biotechnol. Adv. 2011, 29, 375-387, 10.1016/j.biotechadv.2011.02.001.
- Xiao Xiao; Meng He; Yanning Hou; Bilal Abdullahi Shuaibu; Wenjian Dong; Chao Liu; Binghua Yan; Driving Sustainable Energy Co-Production: Gas Transfer and Pressure Dynamics Regulating Hydrogen and Carboxylic Acid Generation in Anaerobic Systems. Processes 2025, 13, 2343, 10.3390/pr13082343.