The aerobic degradation of the blood lipid regulator clofibric acid (CLOF) was studied in a continuous bioreactor treatment using the white-rot fungus Trametes versicolor. Experiments in Erlenmeyer flasks with the compound at 30μgL-1 showed that CLOF can be completely degraded at near environmentally relevant concentration after 4 days. The degradation process was scaled-up in an air-pulsed fluidized bioreactor operated in continuous mode with a hydraulic retention time of 4 days. The results show that 80% of the fed concentration (160μgL-1) was reduced at the steady state (from day 12 to the end). Here, CLOF removal rate was 12.5μgg-1 dry weight biomassd-1. The 2-(4-chlorophenoxy)-2-(hydroxymethyl)propanoic acid (hydroxy-CLOF) was identified as major metabolite, confirming the degradation of CLOF, but its concentration remained constant in the medium. In addition, in a batch bioreactor treatment the undegradability of hydroxy-CLOF was demonstrated. Finally, acute toxicity tests (Microtox) performed with the bacterium Vibrio fischeri showed that the final culture broth in both batch (15min EC50 of 55%) and continuous (11%) experiments were more toxic than the beginning (61%). © 2013.

This work has been supported by the Spanish Ministry of Economy and Competitiveness [projects CTQ2010-21776-C02-01 and Consolider-Ingenio 2010 Scarce CSD2009-00065]. It reflects the authors’ views only. The EU is not liable for any use that may be made of the information contained in it. The Department of Chemical Engineering of the Universitat Autònoma de Barcelona (UAB) is member of the Xarxa de Referència en Biotecnologia de la Generalitat de Catalunya. A. Jelić gratefully acknowledges the JAE Program (Junta para la Ampliación de Estudios –JAE Predoc), co-financed by CSIC (Consejo Superior de Investigaciones Científicas) and European Social Funds, for a predoctoral grant. C. Cruz-Morató acknowledges the predoctoral grant from UAB. S. Perez acknowledges the contract from the Ramón y Cajal Program of the Spanish Ministry of Economy and Competitiveness. Merck is acknowledged for the gift of LC columns. Prof. Barcelo acknowledges King Saud University (Riyadh, Saudi Arabia) for his contract position as Visiting Profesor.

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