Environmental Biotechnology

Electronic Journal of Biotechnology ISSN: 0717-3458 Vol. 10 No. 1, Issue of January 15, 2007
© 2007 by Pontificia Universidad Católica de Valparaíso -- Chile Received May 19, 2006 / Accepted August 4, 2006
DOI: 10.2225/vol10-issue1-fulltext-5  
RESEARCH ARTICLE

Chloroperoxidase mediated oxidation of chlorinated phenols using electrogenerated hydrogen peroxide

Camilo E. La Rotta H.*
Enzyme Technology Laboratory
Institute of Chemistry
Federal University of Rio de Janeiro
UFRJ, CT, Bloco A Sala 539, Ilha do Fundão
CEP 21949-900, Rio de Janeiro, RJ, Brazil
Tel: 55 21 2562 7359
Fax: 5521 2562 7266
E-mail: clarotta@iq.ufrj.br

Eliane D’Elia
Electrochemistry and Electroanalysis Laboratory
Institute of Chemistry
Federal University of Rio de Janeiro
UFRJ, CT, Bloco A Sala 634-A, Ilha do Fundão
CEP 21949-900, Rio de Janeiro, RJ, Brazil
E-mail: eliane@iq.ufrj.br

Elba P.S. Bon
Enzyme Technology Laboratory
Institute of Chemistry
Federal University of Rio de Janeiro
UFRJ, CT, Bloco A Sala 539, Ilha do Fundão
CEP 21949-900, Rio de Janeiro, RJ, Brazil
E-mail: elba1996@iq.ufrj.br

*Corresponding author

Financial support: This work has received financial support from the Brazilian Petroleum Agency (ANP) as a doctoral grant and from The Foundation for Research Support from the State of Rio de Janeiro - FAPERJ - Brazil.

Keywords: biodegradation, bioelectrochemistry, Caldariomyces fumago, chlorinated phenols, chloroperoxidase, hydrogen peroxide electrogeneration.

Abbreviations:

2,4,6-TCP: 2,4,6-trichlorophenol
2,4-DCP: 2,4-dichlorophenol
4-CP: 4-chlorophenol
ABTS: 2,2-azino-bis[3-ethyl-benzothiazoline]-(6)-sulphonic acid
AE: auxiliary electrode
CC C: cathodic chamber control
CP: chlorinated phenols
CPO: chloroperoxidase
DA: direct addition
EG AC: anodic direct oxidation bioelectrochemical processes
EG CC: bioelectrooxidation at the cathodic chamber
EG: electrogeneration
HLT: half-life time
HRP: horse radish peroxidase
P: phenol
PCP: pentachlorophenol
RDE: rotary disk electrode
SCE: saturated calomel electrode
WE: working electrode

Abstract
Full Text

Chloroperoxidase (CPO) from Caldariomyces fumago catalyses the oxidation of several chlorinated phenols (CP) commonly found in industrial waste waters in the presence of hydrogen peroxide. This study compares the direct addition of hydrogen peroxide (DA) with its continuous electrogeneration (EG) during the enzymatic oxidation of CP. Reaction mixtures were studied containing chemically modified CPO, hydrogen peroxide and the phenolic substrates: phenol (P), 4-chlorophenol (4-CP), 2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP) and pentachlorophenol (PCP), in 100 mM sodium-potassium phosphate buffer pH 6.0, at 25ºC. Results were compared in terms of residual phenol concentration (oxidation efficiency), precipitate formation (removal) and residual enzyme activity (stability). With the electrochemical system evaluated at -620 mVSCE, and continuous aeration the maximum H2O2 concentration of 1.2 mM was obtained. Under this conditions and after 4 hrs using EG, no phenol or 4-CP were detected, and 97%, 93% and 88% of 2,4-DCP, 2,4,6-TCP and PCP were degraded, respectively. The use of EG improves enzyme half-life time in comparison to the results obtained by DA.

Supported by UNESCO / MIRCEN network