漆酶对活性黑KN-B和直接大红染料的脱色性能

Decolorization performance of Reactive Black KN-B and Direct Red dyes with laccase

利用白腐真菌漆酶对活性黑KN—B和直接大红2种偶氮染料进行脱色实验。考察反应时间、加酶量、pH值、染料浓度、温度对脱色率的影响，研究了ABTS介体以及金属离子存在下的脱色效果，并分析了漆酶脱色的动力学性能以及其对偶氮染料的降解规律。结果表明，活性黑KN—B和直接大红脱色适宜条件为：反应时间为30min，加酶量8U／mL，pH=7，染料浓度分别为50mg／L和80mg／L，温度40～45℃。ABTS介体对酶促偶氮染料脱色没有明显促进作用。Fe^2＋对漆酶脱色有较强的抑制作用；Cu^2＋对漆酶催化活性黑KN—B促进作用较大，对直接大红影响较小。漆酶对2种染料的脱色反应符合米氏方程，其催化活性黑KN—B和直接大红染料的Km值分别为114．81mg／L，317．5mg／L，vmax值分别为6．57mg／（L·min）和26．0mg／（L·min）。

The degradation of Reactive Black KN-B and Direct Red dyes was investigated using laccase secreted by white rot fung. The influences of reaction time, amount of laccase, pH value, dye concentration, and temperature on decolorization were explored. In addition,the effects of ABTS mediator as well as the metal ions were studied. The kinetics of the enzymatic degradation behavior and the degradation rule of azo dyes were also analyzed. Results show that the optimum decolorization conditions for Reactive Black KN-B and Direct Red are as follows ： reaction time = 30 min, pH = 7, optimum amount of enzyme = 8 U/mL, the optimal concentrations are 50 mg/L and 80 mg/L, respectively,temperature = 40 - 45℃. ABTS can not obviously improve the decolorization. Fe2＋ has strong inhibition to laccase. Cu2＋ can significantly promote the decolorization of Reactive Black KN-B,while it has smaller effect on Direct Red. The laccse-catalyzed degradation obeys Michaelis-Menten equation,the Km values of laccase on Reactive Black KN-B and Direct Red dye are 114.81 mg/L and 317.5 mg/L, Vmax values are 6.57 mg/（ L · min） and 26.0 mg/（L · min）, respectively.