Biodegradation of nitroaromatic compounds in Red Water by white rot fungi Pleurotus ostreatus and floridae

Biodegradação de compostos nitroaromáticos em Água Vermelha pelos fungos de degradação branca Pleurotus ostreatus e floridae

Abstract

Pleurotus fungi are basidiomycetes that stand out in the degradation of recalcitrant organic compounds such as lignin derivatives and phenolic compounds. The aim of this study was to make a comparative evaluation of the capacity of the Pleurotus ostreatus POS 560 and Pleurotus floridae PSP1 fungi in the degradation of 2,4 and 2,6-dinitrotoluene (DNTs) in effluent from an explosive factory. The characterization of the effluent indicated 318 mg L^-1 of DNTs, 246 mg L^-1 of COD and toxicity factor for Daphnia magna corresponding to 8. The conduct of a multivariate study estimated the influence of the variables pH (5.0 and 6.0), co-substrate concentration (10 and 20 g L^-1 of glucose) and species of the fungus Pleurotus (ostreatus and floridae) on the degradation of DNTs, indicating that the variables Fungus and [Glucose] were significant (p <0.05) presenting effects in the order of + 4.45 ± 0.26 and -1.14 ± 0.26, respectively. The reproduction of the best efficiency conditions (P. floridae; pH 6.0 and 10 g L^-1 of glucose) in agitated flasks (100 rpm, 26^oC) was able to carry out, within 14 days of treatment, the removal of organic matter and toxicity factor in levels on the order of 55 and 50%, respectively, in addition to the complete degradation of DNTs which occurred in the first 120 hours of treatment. In this period, the maximum activity of the peroxidase and Mn-peroxidase enzymes was also characterized, suggesting high potential of the bioprocess under study for remediation of effluents contaminated with nitroaromatic compounds.

Keywords:
DNT biodegradation; explosives factory effluent; white rot fungi