Technology Sweetens Air Force Interest in Biomass Research Published May 21, 2009 By Maria Callier Air Force Office of Scientific Research ARLINGTON, Va. -- A lab-funded Virginia Tech scientist is conducting research that will lead to the creation of low-cost hydrogen gas from sugars, a capability that could eventually help decrease greenhouse gas emissions and simultaneously increase energy utilization efficiency. A research team led by Dr. Percival Zhang, university Biofuels Laboratory, developed the new sugar-to-hydrogen technology, leveraging a method gaining recognition as "in vitro synthetic biology." In this case, the method produces hydrogen via the mixture of enzymes with biomass sugar. Dr. Zhang and his team seek to overcome the disadvantages typically associated with the use of low-cost hydrogen as a transportation fuel, drawbacks that include a lack of high-density storage, a costly infrastructure, and various safety concerns. In addressing such challenges, the researchers will pursue their ultimate goal of applying this technology towards transportation fuel independence (i.e., zero reliance on fossil fuels). Synthetic biology combines science and basic engineering to synthesize novel biological functions and systems. In vitro synthetic biology has greater engineering flexibility than its in vivo counterpart. The V-Tech team uses the chemical energy stored in biomass sugar, along with ambient-temperature heat, to split water and release hydrogen. By adding other enzymes to the cocktail, the researchers can even transform cellulose--a major constituent of wood and one composed of sugar links--to hydrogen as well. The scientists are busy stabilizing enzymes in order to increase reaction rates. An unstable enzyme often requires the production of many enzymes to replace it--a consequence rendering commercial hydrogen production via this emergent technology still too costly. Nonetheless, Dr. Zhang believes that this research will gradually yield hydrogen generation rates that are fast enough to power vehicles. With AFRL's funding support, the researchers have been able to prolong enzyme reaction time to 150 hrs. They are working to increase reaction rates a thousandfold through the use of stabilized enzymes. Dr. Zhang anticipates a future wherein sugar-powered vehicles will drive more than 300 mi per "refill." Looking ahead, he further predicts that sugary hydrogen will one day be more advantageous than electrical energy stored in rechargeable batteries (which will replace internal combustion engines once the technology has been improved), because sugar has a much higher energy storage density than does battery-stored electricity.