Fungal wood decay in the presence of fly ash as indicated by gravimetrics and by extractability of low molecular weight volatile organic acids

A mycoremediation system of wood substrate and fungal inoculum was established on an organically poor fly ash deposit at the Šoštanj Thermal Power Plant, Slovenia. A mini-block method with beech wood samples was used to select a suitable fungal isolate for inoculation into the mycoremediation system. Pleurotus ostreatus ZIM 76 proved to be the most appropriate for further tests. Compared to the mass loss in a non-contaminated medium, wood degradation with the selected fungal isolate was reduced by 51% on wood substrate contaminated with 17% (w/w) fly ash. The deterioration processes of wood chips on inoculated and non-inoculated experimental plots were studied by ionic chromatographic analyses of volatile organic acids in water extracts. The presence of P. ostreatus did not influence the concentrations of acetic and formic acids in water extracts from wood chips collected at experimental plots in different intervals from May 2006 to November 2007 comparing inoculated vs. non-inoculated plots.