RESUMO
This study proposes the treatment and valorization of denim textile effluents through a fermentative hydrogen production process. Also, the study presents the decolorizing capabilities of bacterial and fungal isolates obtained from the fermented textile effluents. The maximum hydrogen production rate was 0.23 L H2/L-d, achieving at the same time color removal. A total of thirty-five bacteria and one fungal isolate were obtained from the fermented effluents and screened for their abilities to decolorize indigo dye, used as a model molecule. From them, isolates identified as Bacillus BT5, Bacillus BT9, Lactobacillus BT20, Lysinibacillus BT32, and Aspergillus H1T showed notable decolorizing capacities. Lactobacillus BT20 reached 90% of decolorization using glucose as co-substrate after 11 days of incubation producing colorless metabolites. Bacillus BT9 was able to utilize the indigo dye as the sole carbon source achieving a maximum decolorization of 60% after 9 days of incubation and producing a red-colored metabolite. In contrast, Bacillus BT5 and Lysinibacillus BT32 exhibited the lowest percentages of decolorization, barely 33% after 16 and 11 days of incubation, respectively. When Aspergillus H1T was grown in indigo dye supplemented with glucose, 96% of decolorization was reached after 2 days. This study demonstrates the valorization of denim textile effluents for the production of hydrogen via dark fermentation with concomitant color removal.
Assuntos
Bactérias/metabolismo , Fungos/metabolismo , Hidrogênio/metabolismo , Índigo Carmim/metabolismo , Descoloração da Água , Poluentes Químicos da Água/metabolismo , Biodegradação Ambiental , Corantes/metabolismo , Cinética , Têxteis/análise , Águas Residuárias/microbiologiaRESUMO
Alternative routes to degrade dyes are of crucial importance for the environment. Hence, we report the electrochemical removal of indanthrene blue by using a boron-doped diamond anode, focusing on the toxicity of the treated solutions. Different operational conditions were studied, such as current density (5, 10, and 20 mA cm-2) and electrolyte composition (Na2SO4, Na2CO3, and NaNO3). Besides, the pH was monitored throughout the experiment to consider its direct influence on the ecotoxicity effects. The highest electrochemical oxidation efficiency, measured as color removal, was seen in the 180 min condition of electrolysis in 0.033 M Na2SO4, applying 20 mA cm-2, resulting in a color removal of nearly 91% and 40.51 kWh m-3 of energy consumption. The toxicity towards Lactuca sativa depends solely on pH variations being indifferent to color removal. While the inhibition concentration (IC50) for Raphidocelis subcapitata increases 20% after treatment (in optimized conditions), suggesting that the byproducts are more toxic for this specific organism. Our data highlight the importance of analyzing the toxicity towards various organisms to understand the toxic effect of the treatment applied.
Assuntos
Antraquinonas/análise , Clorófitas/efeitos dos fármacos , Eletrólise/métodos , Lactuca/efeitos dos fármacos , Descoloração da Água/métodos , Poluentes Químicos da Água/análise , Antraquinonas/toxicidade , Boro/química , Clorófitas/crescimento & desenvolvimento , Diamante/química , Eletrodos , Lactuca/crescimento & desenvolvimento , Oxirredução , Poluentes Químicos da Água/toxicidadeRESUMO
Laccases have attracted a great deal of interest because of their remarkable ability for the degradation of synthetic dyes present in wastewaters. New laccase producing sources with robust operational and functional properties are being continuously explored. In this work, the potential for the decolorization and detoxification of synthetic dyes was evaluated in two Mexican strains of the genus Trametes. The decolorization capacity of Trametesmaxima LE130 and Trametes sp. LA1 was tested in solid and liquid media. The phytotoxicity of the degradation products was determined using Raphanussativus and Pisum sativum seeds. In solid media, both strains showed a higher decolorization capacity (p ≤ 0.05) than Phanerochaetechrysosporium ATCC 24725, which is known to be very efficient in lignin and dye-degradation. They produced laccase as the main ligninolytic enzyme; T. maxima LE130 secreted a single isoform of 43.9 kDa, while Trametes sp. LA1 produced three isoforms of 67.3, 58.6 and 52.7 kDa, respectively. Trametes sp. LA1 culture fluids were capable of decolorizing and detoxifying chemically diverse dyes (anthraquinonic dye Remazol Brilliant Blue R, azoic Reactive Black 5 and triphenylmethane Crystal Violet) without the addition of redox mediators. Therefore, this could be considered as a new laccase source which could be potentially competitive in the bioremediation of dye-containing wastewaters.