Investigators: John Regan, Mark Guiltinan, Bruce E. Logan

Hydrogen can fill an important role in the “greening” of global energy technologies: H₂ is not a greenhouse gas, it has 2.4 times the energy content of methane, and its reaction with oxygen in fuel cells produces only pure water. Using hydrogen-based fuel cells avoids pollutants generated directly from high-temperature combustion of organic fuels and eliminates the potential of toxic combustion by-products such as NOx. The advantages of fuel cells are driving a global transition from combustion- to hydrogen-based technologies, particularly in the automobile, oil and energy producing industries. 

Hydrogen is currently produced primarily from fossil fuels via non-sustainable technologies such as steam reforming processes. Biological hydrogen production is possible by two routes: photosynthetic (using algae and photosynthetic bacteria) and fermentative. Fermentative hydrogen production can be accomplished by hydrogen-producing bacteria, such as various Clostridium spp.  Fermentative H₂ production bacteria has advantages compared to photosynthetic routes that include: continuous (versus only during daylight) hydrogen production; capability to convert a variety of carbon sources ; and the ability to recover energy from waste materials produced from agriculture and industry. Large-scale hydrogen production from photo/solar-based technologies will not be feasible due to land and water requirements for growing algae.  In contrast, the infrastructure already exists for a fermentative-based industry with biomass-based substrates. 

We have shown that it is possible to produce a high hydrogen-content gas (50 to 75%) from the fermentation of simple sugars, but the efficiency (overall conversion rate) of biomass materials is only ~50% and needs to be increased. For this project we will genetically engineer Clostridium acetobutylicum in order to increase the efficiency of biohydrogen production.