Molecular Cloning, Characterization, and Dye-Decolorizing Ability of a Temperature- and pH-Stable Laccase from Bacillus subtilis X1
Molecular Cloning, Characterization, and Dye-Decolorizing Ability of a Temperature- and pH-Stable Laccase from Bacillus subtilis X1
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枯草芽孢杆菌 X1 中温度和 pH 稳定的漆酶的分子克隆、表征和染料脱色能力
DOI：
10.1007/s12010-013-0614-3
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发表时间：
2014-02-01
影响因子：
3
通讯作者：
Liao, Xiang-Ru
中科院分区：
文献类型：
--
作者：
Guan, Zheng-Bing;Zhang, Ning;Liao, Xiang-Ru
来自真菌来源的漆酶通常在高温和碱性条件下不稳定。这一特性限制了它们的实际应用。本研究从茴香蜂蜜中分离到一株具有漆酶活性的菌株，经鉴定为枯草芽孢杆菌（Bacillus subtilis）X1。从菌株X1中克隆了CotA-漆酶基因，并在大肠杆菌中以生物活性形式高效表达。纯化的重组漆酶表现出广泛的pH范围内催化底物和高稳定性对碱性pH和高温。在pH 9.0下孵育10天后没有观察到漆酶活性的损失，并且在80 ℃下孵育10小时后检测到约21%的初始活性。在无介体存在的条件下，纯化漆酶可对蒽醌染料（活性蓝4和活性黄棕）和偶氮染料（活性红11和活性艳橙子）进行部分脱色。脱色过程中有效地促进时，甲基精氨酸酯的存在，与超过90%的颜色去除发生在3小时内在pH 7.0或9.0。这些不寻常的性质表明，高潜力的新型CotA-漆酶的工业应用。
Laccases from fungal origin are typically unstable at high temperatures and alkaline conditions. This characteristic limits their practical applications. In this study, a new bacterial strain exhibiting laccase activity was isolated from raw fennel honey samples and identified as Bacillus subtilis X1. The CotA-laccase gene was cloned from strain X1 and efficiently expressed in Escherichia coli in a biologically active form. The purified recombinant laccase demonstrated an extensive pH range for catalyzing substrates and high stability toward alkaline pH and high temperatures. No loss of laccase activity was observed at pH 9.0 after 10 days of incubation, and approximately 21 % of the initial activity was detected after 10 h at 80 degrees C. Two anthraquinonic dyes (reactive blue 4 and reactive yellow brown) and two azo dyes (reactive red 11 and reactive brilliant orange) could be partially decolorized by purified laccase in the absence of a mediator. The decolorization process was efficiently promoted when methylsyringate was present, with more than 90 % of color removal occurring in 3 h at pH 7.0 or 9.0. These unusual properties indicated a high potential of the novel CotA-laccase for industrial applications.