One of DOE’s most enduring goals is to replace fossil fuels with renewable sources of cleaner energy, such as hydrogen produced from plant biomass fermentation. The gut of a termite is helping DOE JGI reach this goal through metagenomics.
The lowly termite is capable of cranking out two liters of hydrogen from fermenting just one sheet of paper, making it one of the planet’s most efficient bioreactors. Termites accomplish this Herculean task by exploiting the metabolic capabilities of about 200 different species of microbes that inhabit their hindguts.
Hydrogen is normally created by using electricity to remove hydrogen molecules from water or natural gas, but the electricity is most often generated using fossil fuels that emit carbon pollutants. The microbial community in the termite gut efficiently manufactures large quantities of clean hydrogen. By sequencing the termite’s microbial community, DOE JGI can provide a better understanding of these biochemical pathways.
Termites eat wood, but they can’t extract energy from the complex lignocellulose polymers within it. These polymers 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. If DOE JGI can figure out which enzymes are used to create hydrogen, and which genes produce them, this process could be scaled up with bioreactors to generate hydrogen from woody biomass, such as poplar, in commercial quantities.