Comparison of strains of Aspergillus niger isolated from natural and artificial substrates from different regions was performed by their ability to produce organic acids and adaptation to stress effects. It was shown strains isolated from plaster coating and natural stone are more active producers of oxalic acid than strains isolated from the surface of wood and paper. Among strains isolated within the same region, oxalic acid hyperproducer strains were more resistant to copper and methatin biocide than oxalic acid strains less active. By sensitivity to zinc in high concentrations among the studied strains of A. niger the variability was not detected. Antarctic strains are more resistant to stress than temperate strains.