Highly virulent wood-rotting Basidiomycetes in cooling tower timbers
J Van Acker, M Stevens, V Rijckaert
Over the past ten years most industrial cooling towers changed their water treatment systems in order to meet environmental requirements. Since this alterations wood rot attack has been reported more frequently. Several Basidiomycete fungi were isolated and determined. Amongst the most important ones are strains of Physisporinus vitreus (Pers.:Fr.) P. Karst., Phellinus contiguus (Fr.) Pat. and Donkioporia expansa (Desm.) Kotl. & Pouz.. In situ total deterioration has been reported of highly durable wood species like azobe (Lophira alata), bangkirai (Shorea leavis) and Californian redwood (Seqouia sempervirens) and of CCA-treated softwood, e.g. Douglas fir. The Donkioporia strain was only recently isolated while on lab-scale research is ongoing to stimulate the growth of Phellinus. The growth under laboratory conditions is not evident for these fungi and different parameters affecting growth were investigated. After altering the malt-agar as medium and improving climatic conditions fungal growth of Physisporinus in laboratory conditions on durable wood has been succesful already. Some preliminary results related to the changes in water treatment are discussed.