Crude oil production is predicted to peak soon. It is unreasonable to assume that conventional fossil fuel sources will continue to meet society’s increasing energy demands for many more decades to come. Concerns about the limited availability of fossil fuels and their negative impact on the environment have urged the scientific community to seek for alternatives that are renewable and more environmentally benign. Amongst the different alternatives available to substitute fossil fuels, hydrogen appears to be the most promising as it has the highest energy content (143 GJ t-1) and on combustion produces water as the only by product. Despite being the most common and abundant element in the universe, molecular hydrogen must be produced from hydrogen rich feedstocks. With the current available technologies, it can be produced from water, biomass or fossil fuel. However, to get the complete benefit of using hydrogen as a carbon neutral fuel, hydrogen production through the biological route is the most promising. The process is accomplished by using inexpensive cell mass that can convert organic biomass into hydrogen.
Abounding microorganisms are known to produce hydrogen. These include the photosynthetic cyanobacteria, green algae and photosynthetic bacteria. These are suitable candidates for solar energy driven biohydrogen production while fermentative bacteria and archaea are considered suitable for fermentative hydrogen evolution using inexpensive organic substrates. The organic substrates may include domestic, farm, agriculture or related industrial wastes that are rich in carbohydrates or peptides. Presently, the disposal of several of these wastes employs expensive procedures. In principle, the use of these wastes for biohydrogen production can solve the twin crisis of waste disposal and green fuel production.
Pursuing this green cause, Prof Debabrata Das and his team of researchers at the Bioprocess Engineering Laboratory, Indian Institute of Technology Kharagpur have been striving for more than a decade to develop inexpensive ways of taking this technology to the industrial scale. As recently published in WIREs Energy and Environment, Khanna and Das, 2012, have holistically described the fermentative biohydrogen production process, including the modeling and optimization of the process for operation in the batch and continuous mode. Further they have discussed the various aspects that presently limit the broad scale application of this technology. However, with continued research efforts and government support the scientists are optimistic that biohydrogen production process would soon transcend from the laboratory to dominate the energy markets of the world.
Khanna N., & Das D. (2012). Biohydrogen production by dark fermentation. Wiley Interdisciplinary Reviews: Energy and Environment, 2, 401-421.
WIREs Energy and Environment