TY - JOUR
T1 - Detoxification and mineralization of Acid Blue 74
T2 - Study of an alternative secondary treatment to improve the enzymatic decolourization
AU - Méndez-Hernández, J. E.
AU - Ramírez-Vives, F.
AU - Solís-Oba, M.
AU - Solís-Oba, A.
AU - Sobrino-Figueroa, A. S.
AU - Loera, O.
N1 - Funding Information:
Acknowledgments Méndez-Hernández JE (Reg. No. 224731) thanks the Mexican National Council for Science and Technology (CONACyT) for the scholarship. The authors also thank the Uni-versidad Autonoma Metropolitana and the Red-Promep for financing this study. The authors declare that they have no conflicts of interest.
PY - 2013/5
Y1 - 2013/5
N2 - Many reports describe the decolourization of dyes by fungal enzymes. However, these enzymes do not contribute to dye mineralization but only to its biotransformation into less coloured or colourless molecules persisting in solution. Therefore, it is essential to analyse the identity of the metabolites produced during enzymatic treatments and its biodegradation into an appropriate system. The present work examines the decolourization/detoxification of a simulated effluent (containing Acid Blue 74) by fungal enzymes and proposes a secondary treatment using an anaerobic system to improve the enzymatic decolourization through the complete mineralization of the dye. Ligninolytic enzymes were produced by solid culture using the thermo-tolerant fungus Fomes sp. EUM1. The enzymes produced showed a high rate of decolourization (>95 % in 5 h) and were stable at elevated temperature (40 °C) and ionic strength (NaCl, 50 mM). Isatin-5-sulphonic acid was identified via 1H-NMR as oxidation product; tests using Daphnia magna revealed the non-toxic nature of this compound. To improve the enzymatic degradation and avoid coupling reactions between the oxidation products, the effluent was subjected to an anaerobic (methanogenic) treatment, which achieved high mineralization efficiencies (>85 %). To confirm the mineralization of isatin-5-sulphonic acid, a specific degradation study, which has not been reported before, with this single compound was conducted under the same conditions; the results showed high removal efficiencies (86 %) with methane production as evidence of mineralization. These results showed the applicability of an anaerobic methanogenic system to improve the enzymatic decolourization/detoxification of Acid Blue 74 and achieve its complete mineralization.
AB - Many reports describe the decolourization of dyes by fungal enzymes. However, these enzymes do not contribute to dye mineralization but only to its biotransformation into less coloured or colourless molecules persisting in solution. Therefore, it is essential to analyse the identity of the metabolites produced during enzymatic treatments and its biodegradation into an appropriate system. The present work examines the decolourization/detoxification of a simulated effluent (containing Acid Blue 74) by fungal enzymes and proposes a secondary treatment using an anaerobic system to improve the enzymatic decolourization through the complete mineralization of the dye. Ligninolytic enzymes were produced by solid culture using the thermo-tolerant fungus Fomes sp. EUM1. The enzymes produced showed a high rate of decolourization (>95 % in 5 h) and were stable at elevated temperature (40 °C) and ionic strength (NaCl, 50 mM). Isatin-5-sulphonic acid was identified via 1H-NMR as oxidation product; tests using Daphnia magna revealed the non-toxic nature of this compound. To improve the enzymatic degradation and avoid coupling reactions between the oxidation products, the effluent was subjected to an anaerobic (methanogenic) treatment, which achieved high mineralization efficiencies (>85 %). To confirm the mineralization of isatin-5-sulphonic acid, a specific degradation study, which has not been reported before, with this single compound was conducted under the same conditions; the results showed high removal efficiencies (86 %) with methane production as evidence of mineralization. These results showed the applicability of an anaerobic methanogenic system to improve the enzymatic decolourization/detoxification of Acid Blue 74 and achieve its complete mineralization.
KW - Complete mineralization
KW - Decolourization
KW - Detoxification
KW - Laccases
KW - Methanogenic conditions
KW - Textile dyes
UR - http://www.scopus.com/inward/record.url?scp=84875751956&partnerID=8YFLogxK
U2 - 10.1007/s11274-012-1235-7
DO - 10.1007/s11274-012-1235-7
M3 - Artículo
C2 - 23247918
SN - 0959-3993
VL - 29
SP - 805
EP - 814
JO - World Journal of Microbiology and Biotechnology
JF - World Journal of Microbiology and Biotechnology
IS - 5
ER -