Decolourization and detoxification of textile industry wastewater by the laccase-mediator system.
Decolourization and detoxification of a textile industry effluent by laccase from Trametes trogii in the presence and the absence of laccase mediators was investigated. Laccase alone was not able to decolourize the effluent efficiently even at the highest enzyme concentration tested: less than 10% decolourization was obtained with 9 U/mL reaction mixture. To enhance effluent decolourization, several potential laccase mediators were tested at concentrations ranging from 0 to 1mM. Most potential mediators enhanced decolourization of the effluent, with 1-hydroxybenzotriazol (HBT) being the most effective. The effect of several physico-chemical parameters that could influence enzyme activity, such as pH, temperature and dye concentration was tested. Optimal decolourization occurred with 20% effluent at pH 5, a temperature of 50 degrees C, and in the presence of 1mM HBT. The toxicities of crude, laccase-HBT treated and laccase-acetosyringone treated effluent were evaluated using the Microtox assay. Only laccase-acetosyringone treated effluent was not toxic; crude and laccase-HBT treated effluent retained toxicity.
Khlifi
Rim
R
Laboratoire des Bioprocédés, Pôle d'Excellence Régionale AUF, (PER-LBP) Centre de Biotechnologie de Sfax, BP: 1177, 3018 Sfax, Tunisie.
Belbahri
Lassad
L
Woodward
Steve
S
Ellouz
Mariem
M
Dhouib
Abdelhafidh
A
Sayadi
Sami
S
Mechichi
Tahar
T
D001673:Biodegradation, Environmental; D019149:Bioreactors; D004396:Coloring Agents; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste; D042845:Laccase / Q000737:chemistry*; D013696:Temperature; D013783:Textile Industry; D013784:Textiles; D055454:Trametes / Q000378:metabolism*; D014865:Waste Disposal, Fluid; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods*
D004396:Coloring Agents; D007220:Industrial Waste; D014874:Water Pollutants, Chemical; D042845:Laccase