Capacidade degradativa de fungos filamentosos indígenas no soro do leite em monocultivos e em co-cultivo com microalga

Abstract

Whey, a byproduct of cheese production, poses an environmental challenge due to its large production and high organic load. In this context, bioremediation emerges as an efficient and cost-effective alternative to treat this effluent compared to traditional methods (chemical and physical). The use of indigenous fungi, naturally found in the studied effluent, brings several advantages to the remediation process, as these fungi are already adapted to its conditions and chemical composition, thus increasing efficiency in degrading contaminants. The use of filamentous fungi and microalgae consortium has been widely studied due to the benefits provided by this symbiotic interaction, which optimizes the removal of nutrients and organic matter. Based on this, the aim of this study is to evaluate the efficiency of different species of indigenous filamentous fungi both individually and in co-cultivation with the microalga Tetradesmus obliquus in removing the pollutant load present in whey, in order to meet the discharge standards set by environmental agencies, aiming to reduce damages economically and sustainably. Advanced treatment of whey, with initial concentrations of 1176.32 ± 8.91 mg.L-1 of Chemical Oxygen Demand (COD), 49.4 ± 2.47 mg.L-1 of Total Nitrogen (TN), and 12.51 ± 0.03 mg.L-1 of Total Phosphorus (TP), was carried out in two stages, both performed in a bubble column reactor, under batch operation mode and constant aeration (1.5 vvm). In the initial stage, each column was inoculated with a pure culture of a selected indigenous filamentous fungus, and in co-cultivation with the microalgae, requiring the addition of constant artificial illumination (100 µmol photons/m²s). The results showed that contaminant removal is significantly enhanced when fungi and microalgae are cultivated in consortium, with the coculture of Cladosporium haloterans and Tetradesmus obliquus standing out, achieving remarkable efficiencies with removals of up to 95.89% for COD, 99.31% for TP, and 88.39% for TN, while the system formed by the fungus alone achieved percentages of 74%, 84.31%, and 72.24% for COD, TP, and TN, respectively. Thus, the use of indigenous fungus-microalgae association potentiated bioremediation, resulting in treated effluent within standards for environmentally safe disposal.