se of free and immobilized cyanobacteria in bioremediation processes of effluents and textile dyes and post treatment of cyanotoxins by ultrasound and fungi: emphasis on ecotoxicological aspects in Danio rerio

Abstract

The growing shortage of water sources ultimately demands alternatives to the treatment of pollutants. Among the many economic sectors that generate effluents, we highlight textiles with the potential to trigger ecotoxicity. Alternatives for the degradation of these effluents and pure dyes, widely used in said activity, are desirable in the environmental problem generated due to the strong demand of these products in the market. In this sense, and with the intention of minimizing the release of other substances toxic to the environment, bioremediation is an efficient alternative, as it brings benefits such as energy and chemical savings, as well as environmental, such as CO2 capture. In this context, cyanobacteria offer an effective solution for the removal of dyes in effluents due to their ability to assimilate various compounds such as: phosphates, nitrates, metals, among others. In view of the above, this research proposal aims to: 1) evaluate the efficacy of dye effluent bioremediation (provided by Dynatec - Itupeva - SP) and pure dyes (Allura red, indigo blue, indigo carmine, pure tartrazine and tartrazine commercial) by the cyanobacteria species Microcystis aeruginosa (immobilized on alginate and free) and Cilindrospermopsis raciborskii (free and immobilized); 2) Find out the growth potential of these cyanobacteria in medium containing concentrations of dyes representative of the textile industry; 3) To detect and quantify the influence of this medium on the toxin production of both strains and 4) To study the efficacy of the post-treatment of these cyanobacteria and cyanotoxins by means of bioremediation with the fungus Pleurotus ostreatus in liquid medium (free and immobilized) and also by ultrasound, investigating the ideal sonication standards for the treatment of cyanotoxins. In this way, it is intended to contemplate in this research two environmental problems, the first being a potential treatment of dyes with cyanobacteria cells and the second, the elimination of these cells and toxins by means of bioremediation by P. ostreatus and ultrasound. After the treatments, it is also intended to evaluate the in vivo and in vitro toxicity reduction of the textile effluent, cyanobacteria and cyanotoxin dyes by means of ecotoxicological tests with different phases of the life cycle of the Danio rerio species. (AU)