Decolorization and detoxification of two textile industry effluents by the laccase/1-hydroxybenzotriazole system.
The aim of this work was to determine the optimal conditions for the decolorization and the detoxification of two effluents from a textile industry-effluent A (the reactive dye bath Bezactive) and effluent B (the direct dye bath Tubantin)-using a laccase mediator system. Response surface methodology (RSM) was applied to optimize textile effluents decolorization. A Box-Behnken design using RSM with the four variables pH, effluent concentration, 1-hydroxybenzotriazole (HBT) concentration, and enzyme (laccase) concentration was used to determine correlations between the effects of these variables on the decolorization of the two effluents. The optimum conditions for pH and concentrations of HBT, effluent and laccase were 5, 1 mM, 50 % and 0.6 U/ml, respectively, for maximum decolorization of effluent A (68 %). For effluent B, optima were 4, 1 mM, 75 %, and 0.6 U/ml, respectively, for maximum decolorization of approximately 88 %. Both effluents were treated at 30 °C for 20 h. A quadratic model was obtained for each decolorization through this design. The experimental and predicted values were in good agreement and both models were highly significant. In addition, the toxicity of the two effluents was determined before and after laccase treatment using Saccharomyces cerevisiae, Bacillus cereus, and germination of tomato seeds.
Laboratoire de Génie Enzymatique et de Microbiologie, Ecole Nationale d'Ingénieurs de Sfax, Université de Sfax, Route de Soukra, Km 4.5, BP 1173, 3038, Sfax, Tunisia.
Ouafa
O
Benzina
Dalel
D
Daâssi
Héla
H
Zouari-Mechichi
Fakher
F
Frikha
Steve
S
Woodward
Lassaad
L
Belbahri
Susana
S
Rodriguez-Couto
Tahar
T
Mechichi
D001409:Bacillus cereus / Q000187:drug effects; D003116:Color; D004396:Coloring Agents / Q000737:chemistry / Q000633:toxicity*; D018525:Germination / Q000187:drug effects; D007220:Industrial Waste; D042845:Laccase / Q000737:chemistry* / Q000378:metabolism; D018551:Solanum lycopersicum / Q000187:drug effects / Q000254:growth & development; D008962:Models, Theoretical; D012441:Saccharomyces cerevisiae / Q000187:drug effects; D012639:Seeds / Q000187:drug effects / Q000254:growth & development; D013783:Textile Industry; D055454:Trametes / Q000201:enzymology; D014230:Triazoles / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods; D062065:Wastewater / Q000737:chemistry / Q000633:toxicity; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000633:toxicity*
D004396:Coloring Agents; D007220:Industrial Waste; D042845:Laccase; D014230:Triazoles; D062065:Wastewater; D014874:Water Pollutants, Chemical; C011852:1-hydroxybenzotriazole