Abstract

This work evaluates linoleic acid peroxidation reactions initiated by Fe 3+-reducing compounds recovered from Eucalyptus grandis, biotreated with the biopulping fungus Ceriporiopsis subvermispora. The aqueous extracts from biotreated wood had the ability to reduce Fe 3+ ions from freshly prepared solutions. The compounds responsible for the Fe 3+-reducing activity corresponded to UV-absorbing substances with apparent molar masses from 3kDa to 5kDa. Linoleic acid peroxidation reactions conducted in the presence of Fe 3+ ions and the Fe 3+-reducing compounds showed that the rate of O 2 consumption during peroxidation was proportional to the Fe 3+-reducing activity present in each extract obtained from biotreated wood. This peroxidation reaction was coupled with in-vitro treatment of ball-milled E. grandis wood. Ultraviolet data showed that the reaction system released lignin fragments from the milled wood. Size exclusion chromatography data indicated that the solubilized material contained a minor fraction representing high-molar-mass molecules excluded by the column and a main low-molar-mass peak. Overall evaluation of the data suggested that the Fe 3+-reducing compounds formed during wood biodegradation by C. subvermispora can mediate lignin degradation through linoleic acid peroxidation. © 2010 Elsevier Ltd.