Wallabies Beat Cows in Methane Showdown

When wallabies chow down on a leafy dinner, they produce about one-fifth the amount of methane that cows do per volume of greens digested. Researchers led by Mark Morrison of the Commonwealth Scientific & Industrial Research Organization—Australia’s national science agency—have now tracked down a species of bacteria in the wallaby gut to explain part of this digestive difference, which could be exploited to reduce greenhouse gas emissions (Science, DOI: 10.1126/science.1205760). Like many gut microbes found in mammals, the anaerobic bacterium, named WG-1, helps wallabies break down starch into sugars for energy production. But instead of producing a lot of methane, the bacterium uses genes for hexose catabolism and carbon dioxide fixation to guide production of succinate via the reductive branch of the natural tricarboxylic acid, or Krebs, cycle; succinate is more benign to the environment and useful to the animal. Morrison and his colleagues propose that more research on WG-1 should be done because it might be possible to alter the gut microbiome of cows and other agricultural ruminants to produce significantly less methane.