In present dissertation work the species composition of microscopic fungi damaging gypsum plasterboard, the physiological properties and resistance to biocidal preparation of micromycetes-contaminants of gypsum plasterboard were studied. The mycobiota of plasterboard constructions of different premises included 25 species of microscopic fungi belonging to 12 genera of Ascomycota division. It was found that in premises under excessive moisture conditions the species number of micromycetes-contaminants of plasterboard considerably exceeded such index for premises with the normal air humidity. It was shown that the main contaminants of plasterboard constructions under climatic conditions of Kyiv were Stachybotrys chartarum, Aspergillus niger, A. sydowii, A. versicolor, A. ustus and Sarocladium strictum. The mycobiota of ordinary unexploited plasterboard was isolated, characterized and compared with the one of moisture resistant plasterboard. More than 50 species of micromycetes were isolated from the surface of cardboard and gypsum core; among them Aspergillus flavipes, Chaetomium globosum, Dicyma aurea and Trichoderma viride occurred often on cardboard and Alternaria chlamydospora, A. infectoria, Cladosporium cladosporioides and S. chartarum – on the gypsum core of plasterboard. During the testing of plasterboard for resistance to fungi we obtained data that indicated that under high air humidity conditions it wasn’t resistant to fungi and didn’t have fungistatic and/or fungicidal activities. It was found that Chaetomium globosum grew on plasterboard at the relative humidity above 90%, while Stachybotrys chartarum – under direct influence of water. Using confocal laser scanning microscopy we confirmed the development of mycelium of micromycetes in the inner layers of the gypsum core of plasterboard. The analysis of such growth characteristics as the radial growth rate of micromycetes were carried out for the selection of optimal concentrations of the medium components. Microscopic fungi were cultivated on mineral Czapek agar medium with addition of powdered plasterboard or its components. The model medium with 5% powdered plasterboard was developed for studying of the physiological properties of fungi. It was conducted that isolated from plasterboard Alternaria infectoria, Aspergillus flavipes, Chaetomium globosum and Stachybotrys chartarum strains inhibited the growth of test-cultures recommended for study of resistance to fungi. It was shown that antagonistic activity of cultures isolated from plasterboard increased on medium with plasterboard and changed the categories of interaction with the prevalence of complete inhibition of test cultures. It was found that micromycetes isolated from the plasterboard had moderate and high enzymatic activities. For example, Aspergillus versicolor F-41226 was characterized by high amylolytic and cellulolytic activities, and Cladosporium cladosporioides F-41230 and C. sphaerospermum F-41232 had high lipolytic activity. According to the results of our study of physiological peculiarities of micromycetes-contaminants of gypsum plasterboard, we determined two groups of microscopic fungi associated with the biodegradation of this substrate under excessive moisture conditions: primary contaminants (S. chartarum and Chaetomium spp.) species that were found on/in the material, and secondary contaminants – species that were present on the material and in the air. To the latter, as a rule, belong Acremonium, Aspergillus, Cladosporium, Penicillium, Trichoderma genera, etc. Primary contaminants were characterized by high competitiveness since they completely inhibited the growth or acted fungicidally on test culture on the model medium with plasterboard. In contrast, secondary contaminants acted fungistatically, neutral or were inhibited by test cultures. Primary contaminants were characterized by higher in 1.2-1.4 values of the radial growth rate compared with the secondary one. The ability to metabolize the cardboard of plasterboard as substrate (cellulolytic activity) of both groups was the same. The values of the enzymatic index of the amylolytic and lipolytic activities of secondary contaminants were equal and higher than in the group of primary contaminants. The antifungal effect of Biotol, Sanitol, Royal Flo and Triora on A. flavipes, N. fischeri, C. globosum and S. chartarum that the most commonly occur on plasterboard was established. Biotol with 0.1% EDTA was the most effective fungicidal preparation against micromycetes isolated from plasterboard. Sanitol that belongs to less toxic class of quaternary ammonium compounds and recommended for use in the premises was characterized by the slightly lower activity.
