Termites may produce up to two litres of hydrogen from digesting a single sheet of paper, making them one of the planet's most efficient bioreactors. Termites achieve this high degree of efficiency by exploiting the metabolic capabilities of about 200 different species of microbes that inhabit their hindguts. The microbial community in the termite gut efficiently manufactures large quantities of hydrogen; the complex lignocellulose polymers within wood are broken down into simple sugars by fermenting bacteria in the termite's gut, using enzymes that produce hydrogen as a byproduct. A second wave of bacteria uses the simple sugars and hydrogen to make the acetate the termite requires for energy. By sequencing the termite's microbial community, the DOE hopes to get a better understanding of these biochemical pathways. If it can be determined which enzymes are used to create hydrogen, and which genes produce them, this process could potentially be scaled up with bioreactors to generate hydrogen from woody biomass, such as poplar, in commercial quantities.
Skeptics regard this as unlikely to become a carbon-neutral commercial process due to the energy inputs required to maintain the system. For decades, researchers have sought to house termites on a commercial scale (like worm farms) to break down woody debris and paper, but funding has been scarce and the problems of developing a continuous process that does not disrupt the termites' homeostasis have not been overcome.