Back in December of 2010, not long after this blog site was first created, I wrote about Garret Suen and his quest to understand the complex biodegradation that occurs within a colony of leaf cutter ants.
People aren’t the only animals that farm. These insects cut leaves apart and carry them to their nests, where they mash them up to give certain types of fungus a medium to grow on. The fungus is supplied with food, which it in turn converts into sugars and fats – substances on which the ants can feed until their little bellies explode.
As I wrote a few years ago, “This is a pretty impressive feat, seeing as how the process successfully converts cellulose– a highly energy-dense substance that gives stems and trees their rigidity – into simple sugars that the ants can digest. This is something that we can’t even do yet. One of the biggest hurdles for creating clean biofuels is figuring out how to break down cellulose. After that point, we pretty much have a good handle on how to convert the sugars into ethanol. But it’s that first step that we’re hung up on.”
At the time, Suen and the leader of the lab, Cameron Currie, were working to figure out how the fungus breaks down this tough organic material. Two-and-a-half years later, they’ve published a paper on their initial results.
Along with Frank Aylward, a bacteriology graduate student and researcher with the Great Lakes Bioenergy Research Center, the scientists sequenced the genomes of every bit of DNA available in the system – including fungi, bacteria, proteins, enzymes, and whatever else was in the mix. They found that while the fungus seems to be doing the lion’s share of the work with specialized enzymes, a diverse group of bacteria is also contributing to the process.
“We think there could potentially be a division of labor between the fungus and bacteria,” said Suen.
The study identifies some potential leads for future work on enzymes. By mixing and matching the newly characterized enzymes with one another and with other, previously known and used biological compounds, the researchers hope to maximize potential industrial-scaled operations that convert tough organics into biofuel.
Whether or not they succeed is yet to be seen. After all, part of the beauty and burden of the leaf cutter ecosystem is its complexity. In an industrial setting, processes must be exact, controlled, and reproducible. Finding a reliable mix of organics and enzymes that work within artificial setting will be a tall order.
The paper, “Leucoagaricus gongylophorus Produces Diverse Enzymes for the Degradation of Recalcitrant Plant Polymers in Leaf-Cutter Ant Fungus Gardens,” was published in the journal Applied and Environmental Microbiology by Suen, Aylward, and a whole host of additional folks. I mean there are a ton listed, and I’m too lazy to copy them over with affiliations and all. Sorry.