Аннотация:Lecanicillium gracile is the recently described species of micromycetes that was obtained from deteriorated mineralmaterials, i.e., limestone and plaster, inside the cultural heritage sites in Russia. Composition of metabolitesin the mycelium and in the culture fluid of L. gracile was characterized and a quantitative analysis of the extracellularpolymer matrix excreted by the fungus was performed. The results of metabolomic analysis of the myceliumrevealed that L. gracile is a promising object for the search for new compounds with biological activity.In the exponential growth phase of L. gracile, the diversity of metabolites in the mycelium was low with the predominantaccumulation of monosaccharides and polyols. In the stationary growth phase, the diversity of metabolitesin the mycelium was high; apparently, biosynthetic processes prevailed over catabolism. L. gracile excretedextracellular polymer substances and changed pH of the medium to an alkaline. Extracellular polymer substancesexcretion not only can contribute to biofilm formation on mineral surfaces but also under alkaline conditionsto secondary calcite precipitation in the case of fungal development on Ca-containing materials (i.e., limestoneand marble). Obtained results reflect specific biochemical characters of L. gracile and its possible mechanismsof mineral materials deterioration.