Biological hydrogen production by dark fermentation: challenges and prospects towards scaled-up production

Among different technologies of hydrogen production, bio-hydrogen production exhibits perhaps the greatest potential to replace fossil fuels. Based on recent research on dark fermentative hydrogen production, this article reviews the following aspects towards scaled-up application of this technology: bioreactor development and parameter optimization, process modeling and simulation, exploitation of cheaper raw materials and combining dark-fermentation with photo-fermentation. Bioreactors are necessary for dark-fermentation hydrogen production, so the design of reactor type and optimization of parameters are essential. Process modeling and simulation can help engineers design and optimize large-scale systems and operations. Use of cheaper raw materials will surely accelerate the pace of scaled-up production of biological hydrogen. And finally, combining dark-fermentation with photo-fermentation holds considerable promise, and has successfully achieved maximum overall hydrogen yield from a single substrate. Future development of bio-hydrogen production will also be discussed.

► Biofilm-based or granule-based type reactor design and developments are strongly recommended for future application in the field of hydrogen production from organic waste. ► Process modeling through CFD simulation has played an important role in reactor scale-up. ► Co-cultures have synergistically increased the rates of substrate conversion and H2 production and yield in the use of cheaper raw material. ► Two main schemes, an integrated process and a sequential process, have been developed to combine dark-fermentation with photo-fermentation processes.