Advances in understanding the ability of sapstaining fungi to produce cell wall-degrading enzymes

The ability of selected sapstaining fungi to produce the enzymes cellulase, xylanase, mannanase, pectinase, and amylase was investigated in vitro. While all test fungi secreted low amounts of xylanase (up to 1.64 mumoles/min/ml) and pectinase (up to 0.11 mumoles/min/ml) into the growth medium, extracellular cellulase was not detected. Furthermore, mannanase was produced only by Ophiostoma piceae (Munch) Syd. & P Syd. (0.29 mumoles/min/ml). To the best of our knowledge, this is the first report of mannanase activity for any Ophiostoma sp. Amylase activity was higher than xylanase, mannanase, and pectinase activities for all test fungi. This confirms that sapstaining fungi preferentially metabolize readily accessible, nonstructural wood components, such as starch. Possible roles of the enzymes detected are discussed.