Wood-degrading capabilities of tropical freshwater fungi

Twelve tropical freshwater fungi, isolated from submerged wood, were select ed to detect their wood-degrading capabilities and the influence of interac tions on the rate of wood decomposition. Wood decay abilities were evaluate d by measuring the percentage weight loss of wood blocks. Wood blocks incub ated in liquid medium or on agar medium, were covered with mycelium, soften ed and had weight losses above 5% after 9 and 12 months. This indicates tha t the fungi tested were able to degrade lignocellulose. Initially, in liqui d cultures, greater weight losses were recorded in all wood blocks inoculat ed with a single inoculum, than those inoculated with the same isolate at o pposite ends of the wood blocks. However, this greater weight loss persiste d for only certain periods depending on the isolates. Wood blocks with thre e fungi showed greater weight losses than wood blocks with the equivalent p aired fungi. For example, Ophioceras dolichostomum and Ophioceras dolichost omum and Nais aquatica or Ophioceras dolichostomum and Nais aquatica and Na is aquatica caused greater weight losses than Ophioceras dolichostomum and Nais aquatica inoculated separately. The greatest weight losses were record ed in the case of three fungi, Ophioceras dolichostomum, Verticillium sp. a nd Nais aquatica inoculated simultaneously on triangular wood blocks. Fungi may act synergistically in order to degrade wood cells.