Action of Fe2O3 and Fe2ZnO4 nanoparticles on strains of actinobacteria and filamentous fungi [Articol]

Abstract

Background: Nanoparticles can exert both beneficial and adverse effects on microorganisms, including DNA modification, accelerated aging, and cell death. They may also act as biostimulants, enhancing the biosynthetic properties of microorganisms of industrial, medical, and agricultural importance. Therefore, studying the effects of nanoparticles on the biosynthesis of biologically active substances is both relevant and necessary. The aim of this study was to evaluate the effects of Fe₂O₃ and Fe₂ZnO₄ nanoparticles on the biosynthesis of biologically active substances in strains of actinobacteria and filamentous fungi. Materials and methods: The study subjects included two actinobacterial strains (Streptomyces gougerotii CNMN-Ac-14 and Streptomyces fradiae CNMN-Ac-11) and three filamentous fungi (Penicillium sp. 7, Penicillium sp. 12, and Penicillium sp. 14). The main parameters assessed were anti-inflammatory and antioxidant activities, along with protein content and catalase activity. Fe₂O₃ and Fe₂ZnO₄ nanoparticles, at concentrations of 1, 5, and 10 mg/L, were tested as stimulators of bioactive compound biosynthesis in the studied strains. The following opportunistic microorganisms were used as test strains: Aspergillus fumigatus, Fusarium solani, Fusarium oxysporum, and the pathogenic yeast Candida albicans. The results indicate that the addition of Fe₂O₃ and Fe₂ZnO₄ nanoparticles to the nutrient medium during subculturing of actinobacteria and filamentous fungi reduced antifungal and antioxidant activities in all studied strains. In the actinobacterial strains Streptomyces gougerotii CNMN-Ac-14 and Streptomyces fradiae CNMN-Ac-11, an increase in catalase activity was observed in variants containing Fe₂ZnO₄ nanoparticles at concentrations of 1–5 mg/L. The highest protein content in the Streptomyces fradiae CNMN-Ac-11 strain was recorded in the variant treated with 1 mg/L Fe₂O₃ nanoparticles, while in the Streptomyces gougerotii CNMNAc14 strain, it was observed in the variant containing 10 mg/L Fe₂ZnO₄ nanoparticles. The fungal strain Penicillium sp. 7 showed stimulation of catalase activity compared to the control sample in the variant treated with 10 mg/L Fe₂ZnO₄ nanoparticles. In the Penicillium sp. 14 strain, enhanced catalase activity was also observed at 10 mg/L Fe₂ZnO₄ nanoparticles, along with an increase in protein content in variants with 5–10 mg/L Fe₂O₃. Regarding the Penicillium sp. 12 strain, the tested nanoparticles exerted a stimulatory effect on protein biosynthesis at 1 mg/L for both Fe₂O₃ and Fe₂ZnO₄. Conclusions: According to the results of this study, it can be concluded that nanoparticles used in the subculturing of microorganisms (actinobacteria and filamentous fungi) can either stimulate or suppress their biosynthetic processes, depending on the strain, nanoparticle composition, and concentration.