Matto Mahreen, Husain Qayyum
Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University, Aligarh-202002, UP, India.
Chemosphere. 2007 Sep;69(2):338-45. doi: 10.1016/j.chemosphere.2007.03.069. Epub 2007 May 23.
The present paper demonstrates the effect of salt fractionated turnip (Brassica rapa) proteins on the decolorization of direct dyes, used in textile industry, in the presence of various redox mediators. The rate and extent of decolorization of dyes was significantly enhanced by the presence of different types of redox mediators. Six out of 10 investigated compounds have shown their potential in enhancing the decolorization of direct dyes. The performance was evaluated at different concentrations of mediator and enzyme. The efficiency of each natural mediator depends on the type of dye treated. The decolorization of all tested direct dyes was maximum in the presence of 0.6mM redox mediator at pH 5.5 and 30 degrees C. Complex mixtures of dyes were also maximally decolorized in the presence of 0.6mM redox mediator (1-hydroxybenzotriazole/violuric acid). In order to examine the operational stability of the enzyme preparation, the enzyme was exploited for the decolorization of mixtures of dyes for different times in a stirred batch process. There was no further change in decolorization of an individual dye or their mixtures after 60 min; the enzyme caused more than 80% decolorization of all dyes in the presence of 1-hydroxybenzotriazole/violuric acid. However, there was no desirable increase in dye decolorization of the mixtures on overnight stay. Total organic carbon analysis of treated dyes or their mixtures showed that these results were quite comparable to the loss of color from solutions. However, the treatment of such polluted water in the presence of redox mediators caused the formation of insoluble precipitate, which could be removed by the process of centrifugation. The results suggested that catalyzed oxidative coupling reactions might be important for natural transformation pathways for dyes and indicate their potential use as an efficient means for removal of dyes color from waters and wastewaters.
本文展示了盐分级芜菁（芜菁）蛋白在各种氧化还原介质存在下对纺织工业中使用的直接染料脱色的影响。不同类型的氧化还原介质的存在显著提高了染料的脱色速率和程度。在所研究的10种化合物中，有6种显示出增强直接染料脱色的潜力。在不同浓度的介质和酶下评估了性能。每种天然介质的效率取决于所处理染料的类型。在pH 5.5和30℃下，所有测试的直接染料在0.6mM氧化还原介质存在下脱色效果最佳。染料的复杂混合物在0.6mM氧化还原介质（1-羟基苯并三唑/紫尿酸）存在下也能最大程度地脱色。为了研究酶制剂的操作稳定性，在搅拌分批过程中，将酶用于不同时间的染料混合物脱色。60分钟后，单个染料或其混合物的脱色没有进一步变化；在1-羟基苯并三唑/紫尿酸存在下，酶使所有染料的脱色率超过80%。然而，混合物过夜放置后，染料脱色没有出现预期的增加。处理后的染料或其混合物的总有机碳分析表明，这些结果与溶液中颜色的损失相当。然而，在氧化还原介质存在下处理这种污染水会导致形成不溶性沉淀，可通过离心过程去除。结果表明，催化氧化偶联反应可能对染料的自然转化途径很重要，并表明它们作为从水和废水中去除染料颜色的有效手段的潜在用途。
