It’s a tough job, but someone’s got to do it. In this case, the “job” is the breakdown of lignin, the structural molecule that gives plants strength and rigidity. One of the most abundant terrestrial polymers (large molecules made of repeating subunits called monomers) on Earth, lignin surrounds valuable plant fibers and other molecules that could be converted into biofuels and other commodity chemicals – if we could only get past that rigid plant cell wall.
Fortunately, the rather laborious process already occurs in the guts of large herbivores through the actions of anaerobic microbes that cows, goats, and sheep rely on to release the nutrients trapped behind the biopolymer. In a paper published in the journal Nature Microbiology, UC Santa Barbara chemical engineering and biological engineering professor Michelle O’Malley and collaborators prove that a group of anaerobic fungi – Neocallimastigomycetes – are up to the task. O’Malley is part of the Department of Energy (DOE)’s Joint BioEnergy Institute (JBEI) where she serves as the Deputy Director for Microbial and Enzyme Discovery. The mission of this group is to explore targeted ecosystems and discover novel microbes and enzymes that break down plant cell walls, and in particular the lignin within them.