Fungal cultures were found on railway sleepers treated with creosote oil, which we assumed to be more resistant to higher concentrations of creosote oil compared to laboratory cultures. For this purpose, we compared the minimum inhibitory concentration of creosote oil on the mycelial growth of the laboratory cultures Pleurotus ostreatus, Hypoxylon fragiforme and Trametes versicolor and the isolated cultures ŽGP3 and ŽGP10. The cultures were exposed to increasing concentrations of creosote oil and mycelial growth was monitored. Creosote oil was mixed with n-hexane at the appropriate concentration. During the 18-day incubation, each Petri dish was scanned several times and the average mycelial growth and standard deviation were calculated. We found that isolated cultures under laboratory conditions have no advantage over laboratory cultures. The ŽGP3 culture was inhibited at a creosote oil concentration of 20 %, while the other cultures were inhibited at a concentration of 50 % or more. The concentration of creosote oil also affects the growth dynamics of the mycelium of the individual cultures. Droplets of secondary metabolites also appeared in certain cultures. We concluded that the minimum inhibitory concentration varied from fungal culture to fungal culture, but was not always higher in cultures isolated from polluted environments. For optimal efficacy of mycoremediation, several parameters need to be considered, starting with the selection of the appropriate microorganism, the substrate, and the composition of the pollutant we want to degrade.
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