Isoperoxidases from hairy root cultures envolved in renoval of phenol and 2,4-dichorophenol

GONZÁLEZ PAOLA S.; BUSTO VICTOR; AGOSTINI ELIZABETH; MIRLRAD SILVIA

Villa Giardino (Córdoba)

Congreso; XV Jornadas Científicas de la sociedad de Biología de Córdoba; 2005

SBC

Peroxidases (Px) had been applied in the removal of phenol and 2,4-dichlorophenol (2,4-DCF), which are highly toxic compounds found in different industrial effluents. In previous studies we have used hairy root cultures (RT) from turnip (RTN) and tomato (RTT) for the removal of phenols. The aim of this study was to perform a biochemical characterization of this process through the use of Px purified from RTT and RTN. The isoenzymes were purified from crude extracts of both RT cultures by ion exchange chromatography. Fractions eluted from the columns were analyzed by isoelectric focusing. The zymograms showed the presence of different basic, neutral and acidic isoenzymes. Removal assays were performed with these isoPx, by incubation with 1 mM H2O2 and phenols (10 mg/l) during 1 hour. Removal efficiencies were estimated by determination of the residual phenolics as described by Klibanov et al. 1980. In most of the assays basic and neutral Px, from both RT cultures, were more efficient for phenol and 2,4-DCF removal than the acidic isoenzymes. These results were correlated with the higher catalytic efficiencies (Ecat) for these substrates found for this group of isoenzymes. Post-removal Px activities were higher for the treatments with acidic Px than those performed with neutral or basic isoenzymes for both phenolic compounds. Those results indicate that basic and neutral Px would be mainly involved in the removal, being inactivated during this action, while the acidic Px were less efficient in the oxidation but more resistant to inactivation. For this reason the acidic isoenzymes would be useful in continuous removal systems.