Macrofungos amazônicos produtores de fenol-oxidases para descoloração de corantes têxteis

Abstract

The effluent produced by the textile industry have intense coloration causing great impact on bodies of water. The methods used in the treatment of these industrial wastes are often ineffective, being necessary to seek new and more effective strategies. One of these, biodegradation refers to the use of microorganisms or their enzymes in the degradation of dyes present in the effluent. In this work the production of phenol oxidase enzymes by Auricularia sp., Coriolopsis sp. and L. crinitus in liquid cultivation and solid state for 14 days. The laccase enzyme characterization was performed using samples which showed the enzyme activity peaks for each of the selected isolates, both in submerged in a solid state. To evaluate the potential of discoloration, 23 dye were exposed to enzymatic action for 72 h. For this test the samples with the highest laccase activity were selected. After enzymatic degradation, toxicity to Daphnia magna effluent assays were performed. In cultivating a solid to increased production of laccase (502, 7 U / g) was measured in marupá substrate by Auricularia sp. In liquid culture, Coriolopsis sp. obtained the highest activity (567,14 IU / ml). Laccases obtained from liquid culture showed optimum temperature of 45 °C, while the highest activities of laccases were between 35 C and 45 C, for cultivation in the solid state. The pH in sodium acetate buffer the highest activities were between 4,0 – 4,5. In McIlvaine buffer were between 3,0 – 4,0. In the bleaching test, enzyme extracts Coriolopsis sp. and L. crinitus degraded dyes Brillante green and Bromocresol green. The dye Acid Blue 80, Remazol brillant blue, Reactive Blue Kn, Reactive Blue 220 and Acid green, the anthraquinone class, after treatment with laccase L. crinitus decolorized when compared to the control. The laccase extracts were not effective in the degradation of azo-dyes, only the Congo red was degraded by laccase Auricularia sp. and L. crinitus. For the toxicity test were used crude extracts liquid cultivation of the three Agaricomycetes. The results obtained in acute toxicity tests on D. magna establish that after the action of enzymes on the dye RBBR the solution with the highest level of toxicity was the Coriolopsis sp. (Toxicity factor (TF) = 32), followed by L. crinitus (TF = 16) and Auricularia sp. (TF = 8). On the other hand the solution with RBBR showed no death of individuals from the concentration of 50% (TF = 2). This fact demonstrates that the pure dye was less toxic than when degraded by the fungal enzymes. Thus removal of an effluent color can not be interpreted as detoxification. The results indicate the potential of Auricularia sp., Coriolopsis sp. and L. crinitus for industrial application and are the starting point for the use of laccases from these strains in processes of removal of dyes from textile effluents.