Many fungal genome projects being carried out at the DOE JGI focus on understanding how enzymes can break down cellulose and lignin, the two most abundant biopolymers on Earth, in order to harness these capabilities for industrial applications such as biofuels production.
Scanning electron micrograph of Ceriporiopsissubvermispora mycelium on wood.
(Robert Blanchette, University of Minnesota)
Another application is biopulping for the paper industry, which requires that the lignin be degraded while leaving the cellulose untouched. Forest products such as pulp and paper account for five percent of the nation’s GDP.
In a study published online March 20, 2012 in the Proceedings of the National Academy of Sciences, an international team of scientists including DOE JGI researchers led by Fungal Genomics Program head Igor Grigorievcomparedthe genomes of two white rot fungi sequenced and annotated by the DOE JGI to learn more about ligninolyticselectivity.
While Phanaerochaete chrysosporiumcan degrade both cellulose and lignin, its close relative Ceriporiopisis subvermisporafocuses on lignin and leaves the cellulose behind, making it the biopulpingfungus of choice.
The researchers found that the C. subvermispora genome had more manganese peroxidases and laccase – enzymes that may speed the degradation of lignin – than the P. chrysosporiumgenome. Study senior author Dan Cullen of the USDA Forest Products Laboratory noted that the paper also suggests the cellulose-degrading portion of C. subvermispora’sgenome is “somewhat repressed” relative to P. chrysosporium, another angle of further study to understand the Ceriporiopisisgenome’s selectivity for lignin.