Brown Rot Fungi Provide Clues for More Efficient Biofuels Production

However, a team of scientists at the University of Minnesota, the U.S. Forest Products Laboratory, University of Wisconsin, Madison, Gyeongsangnam-do Agricultural Research and Extension Services in South Korea, and Pacific Northwest National Laboratory found evidence that brown rot fungi separates the oxidants and enzymes in time rather than in space. The team discovered this two-step wood decomposition mechanism by growing brown rot fungi in one direction along thin wood specimens separating the stages of wood decay linearly across the substrate. The wood was then cut into sections and analyzed for patterns of gene expression.

Researchers found that during the initial part of brown rot colonization, there was evidence of lignocellulose oxidation by reactive oxygen species and an increase in expression of genes important for plant cell wall swelling. These activities would weaken the structural integrity of wood and make it easier for enzymes to access cellulose chains. Then, only at the latter parts of colonization did brown rot fungi begin to produce glycoside hydrolase enzymes that break down cellulose chains into their component sugars.

This unique fungal strategy could provide important new clues for improved conversion of woody plant materials into renewable cellulosic biofuels.