Some Factors Affecting Wood Degradation by Thermophilic and Thermotolerant Fungi

Abstract

Under laboratory conditions, the effects of culture medium, size of wood sample, method of inoculation, duration and temperature of incubation on weight loss of ponderosa pine (Pinus ponderosa Laws.) sapwood were studied. Test wood samples 0.2 X 1.9 X 4.4 cm were planted on fungal cultures using several different media and incubated at temperatures ranging from 25 to 60 C. Incubation periods ranged from 2 to 12 weeks. Fungi grown on Abrams-cellulose or yeast-cellulose medium generally provided the greatest wood substance loss. Maximum wood substance loss occurred during the first 6 weeks of incubation; incubation longer than this seemed unnecessary. No single incubation temperature provided the maximum activity for all the fungi tested, but 40 C or 50 C were optimum temperatures. The greatest weight losses were obtained if the fungi were grown for one week before the wood samples were planted on the cultures. When wood blocks of three different sizes were used, their loss in weight following fungal degradation appeared to be directly related to their volumes and not to their surface areas. Decreasing block size did not result in an increase in rate of weight loss following fungal attack.