Detoxification of extractive constituents in pine wood by sapstain fungi

The toxicity of forest industry effluents to aquatic ecosystems can largely be attributed to lipophilic wood extractives, particularly resin acids and long chain fatty acids. This research examined the ability of ten sapstain fungi to degrade toxic extractive constituents in Scots pine (Pinus sylvestris) pulpwood. After 6 weeks under solid-state fermentation conditions, wood meal samples were extracted with acetone to determine wood extractive losses. The acute toxicity of the acetone extracts was evaluated using the Microtox bioassay. The fungal strains differed greatly in their ability to degrade and detoxify pine wood extractives. The best strain, Ceratocystis conicola, was able to remove up to 55% of the wood extractives and caused a 29-fold decrease in toxicity. The rest of the strains seemed to have limited detoxifying capacity.