Chhabra Meenu, Mishra Saroj, Sreekrishnan T R
Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, Hauz-Khas, New Delhi, India.
Appl Biochem Biotechnol. 2008 Dec;151(2-3):587-98. doi: 10.1007/s12010-008-8234-z. Epub 2008 May 28.
Laccase from basidiomycete fungus Cyathus bulleri was evaluated for its ability to decolorize a number of reactive and acidic dyes in the presence of natural and synthetic mediators. The extent of decolorization was monitored at different mediator/dye concentrations and incubation time. Among the synthetic mediators, 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) was effective at low mediator/dye ratios and resulted in 80-95% decolorization at rates that varied from 226 +/- 4 nmol min(-1) mg(-1) for Reactive Orange 1 to 1,333 +/- 15 nmol min(-1) mg(-1) for Reactive Red 198. Other synthetic mediators like 1-hydroxybenzotriazole and violuric acid showed both concentration- and time-dependent increases in percent decolorization. Natural mediators like vanillin, on the other hand, were found to be less effective on all the dyes except Reactive Orange 1. Computed rates of decolorization were about twofold lower than that with ABTS. The laccase-ABTS system also led to nearly 80% decolorization for the simulated dye mixture. No clear correlation between laccase activity on the mediator and its ability to decolorize dyes was found, but pH had a significant effect: Optimum pH for decolorization coincided with the optimum pH for mediator oxidation. The treated samples were also evaluated for toxicity in model microbial systems. The laccase-mediator system appears promising for treatment of textile wastewaters.
对担子菌真菌布勒地锤菌产生的漆酶在天然和合成介体存在的情况下对多种活性染料和酸性染料进行脱色的能力进行了评估。在不同的介体/染料浓度和孵育时间下监测脱色程度。在合成介体中，2,2'-联氮-双-(3-乙基苯并噻唑啉-6-磺酸)(ABTS)在低介体/染料比例下有效，对于活性橙1，脱色率为80-95%，速率在226±4 nmol min⁻¹ mg⁻¹之间；对于活性红198，速率为1,333±15 nmol min⁻¹ mg⁻¹。其他合成介体如1-羟基苯并三唑和紫尿酸的脱色百分比呈现出浓度和时间依赖性增加。另一方面，发现香草醛等天然介体对除活性橙1之外的所有染料效果较差。计算得出的脱色速率比ABTS的脱色速率低约两倍。漆酶-ABTS系统对模拟染料混合物也导致近80%的脱色。未发现漆酶对介体的活性与其对染料的脱色能力之间存在明显相关性，但pH有显著影响：脱色的最佳pH与介体氧化的最佳pH一致。还在模型微生物系统中对处理后的样品进行了毒性评估。漆酶-介体系统在处理纺织废水方面似乎很有前景。
