Abstract
An environmentally compatible wood preservation was attempted by using whey protein isolate （WPI）, which is a water-soluble protein and derived from milk whey. Sugi （Japanese cedar, Cryptomeria japonica D. Don） sapwood specimens were impregnated with WPI and heated to denature and insolubilize proteins. The fungal decay test using a brown-rot fungus Fomitopsis palustris and a white-rot fungus Trametes versicolor revealed higher durability of WPI-treated wood than control specimens. Their durability was further improved by adding antifungal components such as boric acid and cyproconazole,and the mass loss of 3% or less after decay test was accomplished.
