Identification of terminal structures in cellulose degraded by the brown-rot fungus Postia placenta
T K Kirk, T L Highley, R E Ibach, M D Mozuch
To gain insight into the biochemical mechanism employed by brown-rot fungi to depolymerize cellulose, we identified the end-groups of chemically pure cellulose that had been depolymerized by the brown-rot fungus, Postia placenta. The depolymerized cellulose was acid hydrolyzed and the anion fractions isolated by ion chromatography. Sugar acids were identified by gas chromatographic and mass spectrocopic analysis. Cellulose degraded by Fenton's reagent (H2O2/Fe2+) was also analyzed. The two systems generated the same sugar acids but not in the same quantities. The acids identified include glyceric and erythronic, indicating oxidative cleavage of the vicinal diol carbon-carbon bonds within glucosyl residues in the cellulose polymer. Gluconic and arabonic acids were also identified as major products. No uronic acids were produced in either systems.