An alkaline thermostable laccase from termite gut associated strain of Bacillus stratosphericus.
An alkaline thermostable laccase from termite gut associated strain of Bacillus stratosphericus.
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DOI：
10.1016/j.ijbiomac.2021.02.205
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发表时间：
2021-03
影响因子：
8.2
通讯作者：
Yuanxi Xiao;Jing Li;Pengju Wu;Na Ning;Jingjing Li;Yulong Shen;Qihong Huang;J. Ni
中科院分区：
文献类型：
--
作者：
Yuanxi Xiao;Jing Li;Pengju Wu;Na Ning;Jingjing Li;Yulong Shen;Qihong Huang;J. Ni
漆酶是一种重要的氧化还原酶，广泛分布于多种生物体中。已知白蚁在肠道微生物的帮助下有效分解木质纤维素。然而，很少有漆酶是从白蚁或其肠道微生物中鉴定出来的。我们的目的是筛选能够降解真菌白蚁木质纤维素的菌株。本研究首次从真菌白蚁Macrotermesbarneyi的后肠中分离得到具有木质纤维素分解活性的BacillusstratosphericusBCMC2。漆酶基因（BaCotA）从BCMC2菌株和白蚁肠道宏基因组DNA中克隆。BaCotA在大肠杆菌中过表达，重组BaCotA表现出高比活性（554.1 U/mg）。 BaCotA 具有热稳定性，最佳温度为 70 °C，pH 5.0。此外，BaCotA 还耐碱和有机溶剂。酶在pH 8.0下120分钟仍保持70%以上的残余活性；甲醇、乙醇、丙酮(10%)等有机溶剂对漆酶活性无抑制作用。此外，BaCotA 对靛蓝和结晶紫表现出高效的脱色能力。多种酶学特性表明所提出的漆酶作为工业应用的潜在候选者。此外，这项研究强调白蚁肠道是新菌株或酶的良好资源。
Laccase, an important oxidoreductase, is widely distributed in various organisms. Termites are known to decompose lignocellulose efficiently with the aid of gut microorganisms. However, few laccases have been characterized from termite or its gut microbes. We aimed to screen the strain capable of degrading lignocellulose from fungus-growing termites. In this study,BacillusstratosphericusBCMC2 with lignocellulolytic activity was firstly isolated from the hindgut of fungus-growing termiteMacrotermesbarneyi. The laccase gene (BaCotA) was cloned both from the BCMC2 strain and termite intestinal metagenomic DNA.BaCotAwas overexpressed inE.coli, and the recombinant BaCotA showed high specific activity (554.1 U/mg). BaCotA was thermostable with an optimum temperature of 70 °C, pH 5.0. Furthermore, BaCotA was resistant to alkali and organic solvents. The enzyme remained more than 70% residual activity at pH 8.0 for 120 min; and the organic solvents such as methanol, ethanol and acetone (10%) had no inhibitory effect on laccase activity. Additionally, BaCotA exhibited efficient decolorization ability towards indigo and crystal violet. The multiple enzymatic properties suggested the presented laccase as a potential candidate for industrial applications. Moreover, this study highlighted that termite intestine is a good resource for either new strains or enzymes.