17-19: Brown-rot fungi: model plant cell wall degraders for bioconversion processes

Tuesday, May 1, 2012
Napoleon Ballroom C-D, 3rd fl (Sheraton New Orleans)
Valdeir Arantes1, Jody Jellison2 and Barry Goodell2, (1)Forest Products Biotechnology/Bioenergy Group, University of British Columbia, Vancouver, BC, Canada, (2)Virginia Tech University, Blacksburg, VA
There is growing interest in new routes to better access plant cell wall polysaccharides to facilitate biorefinery fractionation processes, and bioenergy process development. Brown-rot basidiomycetes are the only organisms known able to achieve nearly complete access to the cell wall, and to remove all polysaccharides from plant tissues without causing substantial lignin removal, despite the inability of these organisms to produce a full suite of cellulose depolymerizing enzymes. Brown-rot mechanisms involved in the breakdown of lignified plant cell walls have been acquired as an alternative to the energetically expensive apparatus for lignocellulose breakdown employed by white-rot fungi. The brown-rot mechanism relies, at least in the incipient stage of decay, on the oxidative cleavage of glycosidic bonds in cellulose and hemicellulose, and the extensive oxidative modification and rearrangement of the lignin structure. This is achieved through the direction of highly destructive reactive oxygen species such as the hydroxyl radical, generated nonenzymatically via Fenton chemistry. These modifications in the lignocellulose aid in the selective, near-complete removal of polysaccharides by an incomplete cellulase suite, without significant lignin removal. Such a mechanism could make the production of biofuel and renewable chemicals from lignocellulose biomass more cost effective and energy efficient. This presentation discusses unique features of the non-enzymatic, mediated Fenton reaction mechanism, and how this mechanism initiates changes to major plant cell wall macrocomponents. The implications for biomass processing for biofuels and chemicals are reviewed.
See more of: Poster Session 2
See more of: General Submissions