Hydrogen (H2) is a versatile, clean burning, and renewable energy currency that can
potentially displace the use of petroleum-based fuels in the transportation sector, which accounts for
74% of the total projected increase in liquid fuel consumption over the next 30 years. Demand for
hydrogen is also expected to increase as it starts penetrating the transportation sector as a fuel: about 40
million tonnes of hydrogen per year would be required to fuel about 100 million fuel cell-powered cars
after full market penetration. Hydrogen fuel can be produced from a diverse array of potential
feedstocks including fossil fuels, water, and organic matter using various chemical and electrochemical
methods. Biological hydrogen (biohydrogen) production, which employs the use of hydrogen producing
microorganisms via light dependant or fermentative processes. Research on biohydrogen has increased
dramatically in the past 6 years, with great emphasis on dark fermentation, but there are many scientific
and engineering challenges that must be met by current and future biohydrogen researchers if these
technologies are to be technically feasible and economically viable.
Keywords: Biohydrogen production, numbers of publications, future perspective.
