TP123- Removal of 2,4-DCP using free and immobilized plant peroxidases: toxicity analysis of the post-removal solutions

ANGELINI VA; ADRIÁN GRANERO; A. ZON; MEDINA MI; AGOSTINI E

Congreso; SETAC Latin America 11th Biennial Meeting; 2015

SETAC

Contamination ofnatural waterways is one of the major environmental problems facing the worldand it threatens human health and the environment. Phenolic compounds such as2,4-dichlorophenol (2,4-DCP) are among the most hazardous pollutants. Differentstrategies have been applied to remove phenolic compounds, however toxicityanalysis of the products generated in the process is not done. Plantperoxidases are enzymes that can catalyze oxidation of these compounds usingH2O2 as co-substrate and could potentially be applied for remediation of contaminatedwater. In this work, the potential biotechnological application of totalperoxidase crude extracts (TP) obtained from tobacco (Tab) and turnip (N) hairyroots for 2,4-DCP remediation is analyzed. Removal efficiency of this phenoliccompound was determined using free or immobilized in calcium alginate enzymesand the ion exchange resin carboxymethyl Sephadex (CMS). Subsequently 2,4-DCPand post-removal (PR) solutions toxicity was analyzed using the ANFITOX test,and estimation of the chemical nature of the products generated during theprocess was performed by electrochemical techniques. Application of Tab and Ncrude extracts, both free and immobilized, to 25 mg/l 2,4-DCP solutions allowedto obtain high removal efficiencies. However, these results do not always werecorrelated with a decrease in the toxicity of post-removal (PR) solutions.Electrochemical studies indicated that 2,4-DCP oxidation mechanisms catalyzedby peroxidases are complex and that intermediate compounds formed during thefirst hour of reaction, including quinones, would continue reacting andpolymerizing by spontaneous physico-chemical mechanisms until 48 h afterincubation. The toxicity observed in PR solutions could be attributed to theformation of the intermediate products.