Laccase-catalyzed decolorization of synthetic dyes
Laccase-catalyzed decolorization of synthetic dyes
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DOI：
10.1016/s0043-1354(99)00066-4
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发表时间：
1999-11-01
期刊：
影响因子：
12.8
通讯作者：
Yu, J
中科院分区：
文献类型：
--
作者：
Wong, YX;Yu, J
商业染料由于其独特且稳定的化学结构，在常规好氧处理中并不均匀地易受微生物攻击。利用变色栓菌对蒽醌、偶氮和靛蓝三种典型发色团的合成染料进行了脱色研究。负责染料分解的酶是漆酶，这是一种由真菌在缓慢生长或处于稳定期的条件下释放的胞外氧化酶。然而，漆酶催化染料分解的机理取决于染料的结构。蒽醌染料是漆酶直接氧化的酶底物，偶氮和靛蓝染料的脱色涉及一些小分子（< 8 kDa）代谢产物。结果表明，偶氮染料和靛蓝染料不是漆酶的底物，小分子代谢产物介导了染料和酶之间的相互作用。非底物染料的脱色率实际上是由介导化合物的浓度，而不是漆酶活性在溶液中的限制。一些合成的化合物如2，2 '-连氮双（3-乙基噻唑啉-6-磺酸盐）或ABTS和蒽醌染料也能介导偶氮和靛蓝染料的脱色。定量比较了ABTS和蒽醌染料在两种非底物染料分解过程中的介导作用。这一事实表明，漆酶底物染料在工业废水中可以促进那些非底物染料的脱色。因此，废水脱色可能不受大多数工业废水中真菌不大量产生的小分子代谢物的限制。提出了一种漆酶催化和介体参与的染料降解机理，为进一步的动力学研究奠定了基础。(C)1999爱思唯尔科技有限公司。保留所有权利。
Commercial dyes are not uniformly susceptible to microbial attack in conventional aerobic treatment because of their unique and stable chemical structures. Three synthetic dyes with typical chromophores (anthraquinone, azo and indigo) were decolorized by a white-rot fungus Trametes versicolor. The responsible enzyme for dye decomposition was laccase, an extracellular oxidase released by the fungus under the conditions of slow growth or in its stationary phase. The mechanism of laccase-catalyzed dye decomposition, however, was different depending on dye structures. Anthraquinone dye was an enzyme substrate that was directly oxidized by laccase while decolorization of azo and indigo dyes involved some small molecule (< 8 kDa) metabolites. It was demonstrated that azo and indigo dyes were not the substrates of laccase and the small molecule metabolites mediated the interaction between the dyes and the enzyme. The decolorization rate of the nonsubstrate dyes was actually limited by the concentration of mediating compounds rather than laccase activity in the solutions. Some synthetic compounds such as 2,2'-azino-bis(3-ethylthiazoline-6-sulfonate) or ABTS and anthraquinone dye could also mediate the decolorization of azo and indigo dyes. The mediating function of ABTS and anthraquinone dye was quantitatively compared in the decomposition of two nonsubstrate dyes. This fact implies that the laccase-substrate dyes in an industrial effluent can promote the decolorization of those nonsubstrate dyes. Effluent decolorization, therefore, may not be limited by the small molecule metabolites which are not produced in large amount by fungus in most industrial effluents. A laccase-catalyzed and mediator-involved dye degradation mechanism is proposed For further kinetic studies. (C) 1999 Elsevier Science Ltd. All rights reserved.