Biotech Production of Hydrogen
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This would seem a worthy pursuit for the biotech industry. Still looking for biotech companies that may be engaged in this sort of research.
5.4 Enhancement of hydrogen-producing capabilities through genetic engineering
Although genetic studies on photosynthetic microorganisms have markedly increased in recent times, relatively few genetic engineering studies have focused on altering the characteristics of these microorganisms, particularly with respect to enhancing the hydrogen-producing capabilities of photosynthetic bacteria and cyanobacteria. As described in Section 5.3.2., some nitrogen-fixing cyanobacteria are potential candidates for practical hydrogen production. Hydrogen production by nitrogenase is, however, an energy-consuming process due to hydrolysis of many ATP molecules. On the other hand, hydrogenase-dependent hydrogen production by cyanobacteria and green algae is "economic" in that there are no ATP requirements. This mechanism of hydrogen production is not however sustainable under light conditions. Water-splitting by hydrogenase is potentially an ideal hydrogen-producing system. Asada and co-workers (21, 22) attempted to overexpress hydrogenase from Clostridium pasteurianum in a cyanobacterium, Synechococcus PCC7942, by developing a genetic engineering system for cyanobacteria. These workers also demonstrated that clostridial hydrogenase protein, when electro-induced into cyanobacterial cells is active in producing hydrogen by receiving electrons produced by photosystems (23).
Another strategy being examined is the enhancement of hydrogen-producing capabilities of photosynthetic bacteria. In nitrogenase-mediated hydrogen-producing reactions, a considerable amount of light energy which is converted to biochemical energy by the photosystem, is lost through various biochemical processes. Control of the photosystem at an appropriate level for nitrogenase activity, would result in reduced energy losses, and thus improved light energy conversion. To this end, with the objective of utilizing genetic engineering techniques in controlling the photosystem level in the potent hydrogen-producing photosynthetic bacteria Rhodobacter sphaeroides RV, the puf operon encoding photoreaction center and light-harvesting proteins was isolated and characterized (24).
5.5 Research and development on biological hydrogen production
As explained in the introduction to this chapter, biological hydrogen production is now receiving much attention as an environmentally acceptable technology. Although a few research groups are active in basic or applied fields of hydrogen production, recent world-wide environmental problems have prompted the formation of national projects for biological hydrogen production. The German Federal Ministry for Research and Technology funded a biological hydrogen production project (1989-1994), in which universities undertook basic research. In Japan, the Ministry of International Trade and Industry is promoting a project for biological hydrogen production by environmentally acceptable technology (1991-1998) through the Research Institute of Innovative Technology for the Earth (RITE), with financial support of the New Energy and Industrial Development Organization (NEDO). The project includes development of total technologies for biological hydrogen production, the screening and breeding of microorganisms, and basic research and development of photobioreactors and anaerobic bioreactors.
The Hydrogen Committee of the International Energy Agency (IEA, under the auspices of the OECD) has rearranged Annex Committees for hydrogen technologies. The target of Annex 10 is the photoproduction of hydrogen. This consists of three subtasks: i) photoelectrochemical hydrogen production, ii) photobiological hydrogen production, and iii) standardization. The three-year plan (1995-1997) aims to establish a closely collaborative world-wide research network to promote hydrogen production technologies.
5.6 Future prospects
Biological hydrogen production is the most challenging area of biotechnology with respect to environmental problems. The future of biological hydrogen production depends not only on research advances, i.e. improvement in efficiency through genetically engineering microorganisms and/or the development of bioreactors, but also on economic considerations (the cost of fossil fuels), social acceptance, and the development of hydrogen energy systems. |
