黄瓜新杆菌漆酶的表征及在工业染料脱色中的应用

Characterization of Laccase from Neobacillus cucumis and Its Application in Industrial Dye Decolorization

摘要:

漆酶具有染料脱色、织物表面改性和纺织品漂白的能力，因此在纺织工业中有着广泛的用途。筛选一种具有碱稳定性且适合纺织染料脱色应用的漆酶具有挑战性。该研究从黄瓜新杆菌（Neobacillus cucumis）中获得了一种新型碱性漆酶LacNC，并在大肠杆菌中进行了表达。LacNC是一种单体蛋白，其分子量大小为58 ku。LacNC以2,6-二甲氧基苯酚、丁香醛连氮（SGZ）和愈创木酚分别作为底物，其最适pH值分别为6.0、7.0和8.0。以愈创木酚为底物，LacNC最适温度为55 ℃。LacNC在pH值5.0~11.0范围内保持85%以上活性。在40 ℃孵育1 h后，保持80%以上活性。此外，LacNC对靛蓝胭脂红和孔雀石绿处理3 h，脱色率分别为90%和80%以上，对活性黑B的脱色率在24 h可达85%。综上所述，该研究获得了一种新型碱性漆酶，在碱性条件下对合成染料展现出较高的脱色效率，表明该漆酶是用于纺织工业废水处理的环保候选者。

Abstract:

Laccase is widely used in the textile industry for dye decolorization, fabric surface modification, and textile bleaching. Screening for a laccase that is alkaline stable and suitable for textile dye decolorization is challenging. A novel alkaline laccase (LacNC) was obtained from Neobacillus cucumis and expressed in Escherichia coli. LacNC is a monomeric protein with a molecular weight of 58 ku. The optimum pH values for LacNC were 6.0, 7.0, and 8.0 when 2,6-dimethoxyphenol, syringaldazine (SGZ), and guaiacol, respectively, were used as substrates. The optimal temperature for LacNC was 55 ℃ for the guaiacol substrate. The activity of LacNC remained more than 85% in the pH range of 5.0~11.0. After incubation at 40 ℃ for 1 h, the activity of LacNC was still higher than 80%. In addition, the decolorization rates of indigo carmine and malachite green by LacNC were more than 90% and 80% in 3 h, respectively, and the decolorization rate of reactive black B by LacNC reached 85% in 24 h. In this study, a new alkaline laccase demonstrating high decolorization efficiency for synthetic dyes under alkaline conditions was obtained. Hence, this laccase is an environmentally friendly candidate for treating wastewater in the textile industry.