Bioprospecção de células fúngicas imobilizadas em espumas comerciais de poliuretano na remoção de fósforo de efluentes domésticos

Abstract

Fungi are known to degrade a wide variety of materials and compounds. One of the objectives of this study to analyze the effect of time on the number of scientific production on bioremediation of effluents using fungi, to evaluate the types of bioremediative pollutants, and the countries that have used it is approach. As a result of the search for the key words, 3,665 articles were identified in the Web of Science database, but 1,877 directly addressed the theme. The year with the largest number of articles published was in 2020. Most articles investigate the removal of dyes by fungi, followed by phenolic compounds, chemical oxygen demand, heavy metals and pharmaceutical compounds, respectively. The countries with the most collection points were India, Spain, China, the United States, Brazil and Turkey, respectively. The countries with the most collection points were India and Spain, respectively. Another objective of this work was to select fungal isolates with potential to produce phosphatases and develop a product capable of removing phosphorus from domestic effluents. After screening of 12 fungic isolates in quatitative and qualitative enzymatic tests for phosphate production, Aspergillus flavus, Aspergillus niger, Talaromyces pinophilus and Trichoderma asperellum were selected as efficient phosphatase producers and candidates to remove phosphorus from domestic effluents. The fungal isolates were incubated in a minimum culture medium containing potassium phosphate ranging from 1g L-1 to 4g L-1 to induce phosphatase production. Commercial polyurethane foams were cut into 1.0 cm x 1.0 cm x 0.7 cm cobblestones. So the fungal biomass. it was inoculated in a minimum medium containing 5g of cobblestones (0.71 mm3) of previously autocled commercial polyurethane foams. Microorganisms grew for 12 days and during this period, the fungi trapped in the foams were monitored by the characteristic color of each fungus, followed by the measure of acid phosphatase activity with p-nitrophenyl phosphate. A factorial planning 32 was constructed to verify the influence of immobilization time (Ti) and foam supply (E) on the production of phosphatase by fungi. Subsequently, a new factorial planning 52 was constructed to simultaneously evaluate the effects of reaction time and domestic effluent volume. All fungi produced phosphatase in the immobilized system, being A. niger for 12 days, followed by T. asperellum for 11 days and A. flavus and T. asperellum for 7 days. The isolates A. niger and A. flavus showed higher phosphatase activity (229 μmol/h), after 192 and 96 h, respectively. T. pinophilus and T. asperellum showed higher enzymatic activity (AE) after 72 h, with 37.7 and 78 μmol/h for T. asperellum T. pinophilus, respectively. Immobilization time and foam supply significantly influenced phosphatase production. The maximum phosphatase activity was xi obtained with 96 h of immobilization and 9 foam cobblestones for A. flavus; for the fungi T. pinophilus and T. asperellum, the maximum phosphatase activity was obtained with 72 h of immobilization and 12 foam cobblestones; and for A. niger 72 h and 15 foam cobblestones. The mathematical model central rotational composite planning was used to verify the optimization of immobilization time and foam supply. The coefficient of determination (R2) on the influence of factors on enzymatic activity was 0.938 for A. flavus; 0.867 for A. niger; 0.997 for T. pinophilus. and 0.955 for T. asperellum. The immobilized system of A. flavus, A. niger, and T. asperellum was able to remove 99.9% of phosphorus in 1h10m; and T. pinophilus., 99.9% of phosphorus in 2 h. All fungal isolates are potential bioremediats of phosphorus in domestic effluents.