Avaliação do uso de Microcystis aeruginosa e Cylindrospermopsis raciborskii na redução da coloração e ecotoxicidade de corantes puros e em efluentes têxteis
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Data
2022-09-16
Autores
Lira, Vivian Silva
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Universidade Estadual Paulista (Unesp)
Resumo
A crescente escassez de fontes de água potável, bem como o cumprimento obrigatório de exigências legais para lançamento em corpos d’água ou rede coletora de esgotos, acabam demandando alternativas para o tratamento de efluentes. Entre os inúmeros setores que geram efluentes com potencial de toxicidade, o têxtil se destaca. As indústrias têxteis geram grande quantidade de efluentes com uma carga de corantes que são naturalmente de difícil degradação. Uma alternativa para remediação desses corantes é fundamental e, entre os possíveis tratamentos, a biorremediação é uma alternativa. Esta pesquisa teve por objetivo avaliar o potencial de biorremedição de corantes têxteis (tartrazina e índigo blue) e efluentes têxteis pelas cianobactérias Microcystis aeruginosa e Cylindrospermopsis raciborskii. A viabilidade da biorremediação foi avaliada através da toxicidade dos corantes e efeito da coloração sobre as cianobactérias, com contato direto e indireto. Analisou-se o crescimento celular por meio de contagem e a descoloração por meio de espectrofotometria. Também analisou-se a eficiência da biorremediação na descoloração de efluentes provenientes de uma fábrica de jeans e outra de tapetes pela duas espécie de cianobactérias. Os experimentos de biorremediação ocorreram durante 25 dias com amostras de efluentes brutos e também diluídos em 50%. Testes ecotoxicológicos foram realizados com larvas de Danio rerio (parâmetros sobrevivência e crescimento) antes e após a biorremediação. Os resultados demonstraram que a Microcystis aeruginosa cresceu significativamente em contato direto com o corante amarelo tartrazina, mas em contato indireto houve redução no crescimento com ambos corantes. Em contrapartida, a Cylindrospermopsis raciborskii não apresentou um crescimento satisfatório com a tartrazina e foi inibida pelo corante índigo blue. Observou-se redução da cor no efluente de tapetes em 43% na presença da M. aeruginosa e 34,6% na ausência dela, sem redução de toxicidade. Conclui-se, portanto, que M. aeruginosa tem potencial para crescer em elevadas concentrações de amarelo tartrazina (500 mg/L) e degradar esse corante. Os efluentes têxteis, devido à sua alta complexidade, não são facilmente degradados e apresentaram toxicidade para ambas as cepas. Tempos menores de biorremediação devem ser contemplados, com base nos dados de descoloração, onde o metabolismo deve ser estimulado, por manipulações do efluente, em favor da viabilidade celular exponencial.
The growing scarcity of drinking water sources, as well as the mandatory compliance with legal requirements, end up demanding alternatives for the treatment of effluents. Among the numerous sectors that generate effluents with the potential for toxicity, textiles stand out. The textile industries generate large amounts of effluents with a load of dyes that are naturally difficult to degrade. An alternative for the remediation of these dyes is essential and, among the possible treatments, bioremediation is an alternative. This research aimed to evaluate the bioremediation potential of textile dyes (tartrazine and indigo blue) and textile effluents by the cyanobacteria Microcystis aeruginosa and Cylindrospermopsis raciborskii. The viability was evaluated through the toxicity of the dyes and the effect of the stain on the cyanobacteria, with direct and indirect contact. Cell growth was analyzed by counting and discoloration by spectrophotometry. We also analyzed the efficiency of bioremediation in the discoloration of effluents from a jeans factory and a carpet factory by the two species of cyanobacteria. The bioremediation experiments took place with samples of raw effluents also diluted by 50%. Ecotoxicological tests were performed with Danio rerio larvae (survival and growth parameters) before and after bioremediation. The results showed that Microcystis aeruginosa grew significantly in direct contact with the yellow dye tartrazine, but in indirect contact, there was a reduction in growth with both dyes. On the other hand, Cylindrospermopsis raciborskii did not show satisfactory growth with tartrazine and was inhibited by the indigo blue dye. A reduction in color was observed in the effluent of carpets by 43% in the presence of cyanobacteria and 34.6% in the absence of them, with no reduction in toxicity. It is concluded, therefore, that M. aeruginosa has the potential to grow in high concentrations of tartrazine yellow (500 mg/L) and to degrade this dye. Textile effluents, due to their high complexity, are not easily degraded and are toxic to both strains. Shorter bioremediation times must be considered, based on the discoloration data, where metabolism must be stimulated, by manipulations of the effluent, in favor of exponential cell viability.
The growing scarcity of drinking water sources, as well as the mandatory compliance with legal requirements, end up demanding alternatives for the treatment of effluents. Among the numerous sectors that generate effluents with the potential for toxicity, textiles stand out. The textile industries generate large amounts of effluents with a load of dyes that are naturally difficult to degrade. An alternative for the remediation of these dyes is essential and, among the possible treatments, bioremediation is an alternative. This research aimed to evaluate the bioremediation potential of textile dyes (tartrazine and indigo blue) and textile effluents by the cyanobacteria Microcystis aeruginosa and Cylindrospermopsis raciborskii. The viability was evaluated through the toxicity of the dyes and the effect of the stain on the cyanobacteria, with direct and indirect contact. Cell growth was analyzed by counting and discoloration by spectrophotometry. We also analyzed the efficiency of bioremediation in the discoloration of effluents from a jeans factory and a carpet factory by the two species of cyanobacteria. The bioremediation experiments took place with samples of raw effluents also diluted by 50%. Ecotoxicological tests were performed with Danio rerio larvae (survival and growth parameters) before and after bioremediation. The results showed that Microcystis aeruginosa grew significantly in direct contact with the yellow dye tartrazine, but in indirect contact, there was a reduction in growth with both dyes. On the other hand, Cylindrospermopsis raciborskii did not show satisfactory growth with tartrazine and was inhibited by the indigo blue dye. A reduction in color was observed in the effluent of carpets by 43% in the presence of cyanobacteria and 34.6% in the absence of them, with no reduction in toxicity. It is concluded, therefore, that M. aeruginosa has the potential to grow in high concentrations of tartrazine yellow (500 mg/L) and to degrade this dye. Textile effluents, due to their high complexity, are not easily degraded and are toxic to both strains. Shorter bioremediation times must be considered, based on the discoloration data, where metabolism must be stimulated, by manipulations of the effluent, in favor of exponential cell viability.
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Palavras-chave
Biorremediação, Cianobacteria, Corantes, Peixe-zebra, Bioremediation DLC, Coloring matter, Zebrafish