BACKGROUND AND OBJECTIVES Antibiotics such as tetracycline are key examples of micropollutants, chemicals found in the environment at very low concentrations (μg/L to ng/L). Improper disposal from the hospitals, livestock, and poultry industries, as well as the fact that most consumed antibiotics are not fully absorbed, leads to their accumulation in the environment. Antibiotics pose significant ecological risks like changes in microbial diversity, increased the antibiotic resistance, cells toxicity, endocrine disruptions, and adverse effects on the plant photosynthesis. While the conventional wastewater treatments are usually ineffective at removing these micropollutants, alternative methods such as biosorption, the immobilization of pollutants by inactive biomass from the biological origin, are preferred. Fungi are outstanding biosorbents due to their cellular morphology, cell wall composition, and diverse metabolic abilities. In this study, we used a filamentous fungus isolated from tannery waste-polluted soil, to remediate tetracycline hydrochloride through the biosorption process. MATERIALS AND METHODS Strain PN5 was isolated from polluted soil of the Charmshahr area of Mashhad. To obtain the fungal biomass, strain PN5 was inoculated in Potato Dextrose Broth and kept for 96 h at 28°C. After incubation, the fermentation broth was centrifuged, and the cell pellets were freeze-dried and powdered to a uniform particle size. The absorption process was conducted with a reaction mixture containing 0.05 mg/ml of tetracycline and 2 mg/ml of fungal biomass. The mixture, along with a control sample, was incubated at 28 °C and 150 rpm for 1 h. After incubation, the supernatant was separated by centrifugation. Absorption efficiency was determined by measuring the optical density at 357 nm using UV-Visible spectrometry RESULTS AND DISCUSSION The absorption process resulted in a 43% reduction in tetracycline concentration, demonstrating effective absorption of the pollutant by the fungal biomass. This research focused on removing the tetracycline micropollutant from the environment using a simple, cost-effective, and eco-friendly method. The results demonstrate that filamentous fungi biomasses isolated from environments with high concentrations of heavy metals are effective absorbents due to their biodegradable nature and functional groups for binding pollutants. These fungi can efficiently absorb tetracycline with minimal restrictions and costs. This approach not only conserves resources such as money, time, and energy but also provides a highly efficient and low-impact alternative to traditional pollutant removal methods.

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