The present study aimed to identify airborne molds of the Aspergillus genus and to determine the secondary metabolite profiles and toxicity of dominant fungal species isolated from various locations in the Wroclaw Zoological Garden. Air samples were collected using a MAS-100 air sampler and analyzed for fungal colony-forming units (CFU). Morphological and molecular methods, including ITS sequencing, were employed for dominant mold identification. The most frequently encountered species were A. fumigatus and A. niger, while A. pseudoglaucus and A. nomius were the least common. The high prevalence of species from sections Nigri, Flavi, and Fumigati suggests their adaptability to the zoo environment. A total of 17 Aspergillus isolates were analyzed for both their capacity to induce cellular toxicity and their production of mycotoxins. The results indicated that all isolates exhibited cellular toxicity, with 70.6% displaying levels of toxicity that were medium to high. Furthermore, the mycotoxicological analysis revealed that only A. fumigatus strains were capable of producing mycotoxins, specifically gliotoxin. The study underscores the discrepancy between the levels of toxicity and the production of mycotoxins, thereby suggesting the presence of additional cytotoxic metabolites. These findings emphasize the need for a comprehensive understanding of the complex interplay between fungal metabolites and their consequences for human health.

Coolants containing glycols, corrosion inhibitors and anti-foaming additives pose a significant environmental risk due to their limited susceptibility to natural degradation. At the same time, glycols are valuable raw materials widely used across industrial sectors, and global consumption of ethylene glycol, the principal component of most coolants, has been steadily increasing. Microbial biodegradation offers an economically and environmentally attractive route for treating spent coolants. In this study, fourteen environment-derived strains from a culture collection, thirteen bacteria and one yeast, were screened for the ability to grow on two chemically distinct industrial coolant matrices: an unused, ethylene-glycol-based product (Petrygo Q NEW) and a propylene-glycol-dominated spent fluid drained from an engine cooling system. Six strains (AC2/2, B3J, 5A, B9F, B16B and 17E) showing the highest growth potential were subjected to adaptive laboratory evolution (ALE) by serial passaging for ten transfers in a minimal medium containing 1.5 g L⁻¹ yeast extract, in which the coolant provided the principal carbon and energy source. Growth dynamics of evolved and ancestral strains were compared by microplate cultivation, glycol depletion was quantified by high-performance liquid chromatography (HPLC) in shake-flask cultures, and tolerance was assessed by spot assays. Adaptation was strain-specific and was generally more pronounced on the spent, propylene-glycol-dominated fluid than on the unused, ethylene-glycol-based product. After selection, removal of ethylene glycol from the spent fluid within 96 h increased from 33.3% to 79.7% for Wickerhamomyces anomalus B16B and from 24.8% to 60.1% for Bacillus sp. B9F, while Pseudomonas sp. AC2/2 depleted 64.3% of the propylene glycol present that is 25.6 g L⁻¹ and the largest mass removed from either matrix. In the unused, ethylene-glycol-based product, removal also increased after ALE, reaching 10.9 g L⁻¹ for AC2/2 from an initial load of about 50 g L⁻¹, but none of these differences were significant. To the best of our knowledge, this is the first application of ALE to an intact commercial coolant and to a spent fluid drained from an engine cooling system, and it demonstrates that non-modified environmental isolates can be improved for the treatment of this hazardous waste stream without genetic modification.