natural mushroom (fungi) growth on wood is a solid state process of fermentation process and this can be further harnessed technological.More work have been reported on sold state fermentation of wood products like sawdust, example is "comparative degradation of sawdust by micro organisms isolated from it" by J. A. Lennox, et. al (2010). African Journal of Micobiology Research Vol. 4(17), pp. 1804-1807, www.academicjournals.org/ajmr . one of my on going project is optimizing the solid state fermentation of sawdust, using filamentous fungi, Aspergilus niger and Penicillium spp.