Carl J. Houtman

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The brown rot fungus Gloeophyllum trabeum uses an extracellular hydroquinone-quinone redox cycle to reduce Fe(3+) and produce H(2)O(2). These reactions generate extracellular Fenton reagent, which enables G. trabeum to degrade a wide variety of organic compounds. We found that G. trabeum secreted two quinones, 2,5-dimethoxy-1,4-benzoquinone (2,5-DMBQ) and(More)
The fungi that cause brown rot of wood initiate lignocellulose breakdown with an extracellular Fenton system in which Fe(2+) and H(2)O(2) react to produce hydroxyl radicals (.OH), which then oxidize and cleave the wood holocellulose. One such fungus, Gloeophyllum trabeum, drives Fenton chemistry on defined media by reducing Fe(3+) and O(2) with two(More)
Brown rot basidiomycetes initiate wood decay by producing extracellular reactive oxygen species that depolymerize the structural polysaccharides of lignocellulose. Secreted fungal hydroquinones are considered one contributor because they have been shown to reduce Fe(3+), thus generating perhydroxyl radicals and Fe(2+), which subsequently react further to(More)
It is often proposed that brown rot basidiomycetes use extracellular reactive oxygen species (ROS) to accomplish the initial depolymerization of cellulose in wood, but little evidence has been presented to show that the fungi produce these oxidants in physiologically relevant quantities. We used [(14)C]phenethyl polyacrylate as a radical trap to estimate(More)
Since uncertainty remains about how white rot fungi oxidize and degrade lignin in wood, it would be useful to monitor changes in fungal gene expression during the onset of ligninolysis on a natural substrate. We grew Phanerochaete chrysosporium on solid spruce wood and included oxidant-sensing beads bearing the fluorometric dye BODIPY 581/591 in the(More)
Building on our laboratory-scale optimization, oxalic acid was used to pretreat corncobs on the pilot-scale. The hydrolysate obtained after washing the pretreated biomass contained 32.55g/l of xylose, 2.74g/l of glucose and low concentrations of inhibitors. Ethanol production, using Scheffersomyces stipitis, from this hydrolysate was 10.3g/l, which(More)
Oxidative cleavage of the recalcitrant plant polymer lignin is a crucial step in global carbon cycling, and is accomplished most efficiently by fungi that cause white rot of wood. These basidiomycetes secrete many enzymes and metabolites with proposed ligninolytic roles, and it is not clear whether all of these agents are physiologically important during(More)
Basidiomycetes that cause brown rot of wood are essential biomass recyclers in coniferous forest ecosystems and a major cause of failure in wooden structures. Recent work indicates that distinct lineages of brown rot fungi have arisen independently from ligninolytic white rot ancestors via loss of lignocellulolytic enzymes. Brown rot thus proceeds without(More)
The organization of polyiodide chains in the amylose-iodine complex was investigated by Raman spectroscopy, by UV/vis, and by second-derivative UV/vis spectroscopies complemented by semiempirical calculations based on a simple structural model. The Raman spectra indicate that the primary substructures of the polyiodide chains are I–3; and I; sub-units. The(More)
Brown rot basidiomycetes have an important ecological role in lignocellulose recycling and are notable for their rapid degradation of wood polymers via oxidative and hydrolytic mechanisms. However, most of these fungi apparently lack processive (exo-acting) cellulases, such as cellobiohydrolases, which are generally required for efficient cellulolysis. The(More)