Characterization and functional gene analysis of a newly isolated indole-degrading bacterium Burkholderia sp. IDO3
Characterization and functional gene analysis of a newly isolated indole-degrading bacterium Burkholderia sp. IDO3
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新分离的吲哚降解菌伯克霍尔德氏菌的鉴定和功能基因分析。
DOI：
10.1016/j.jhazmat.2018.12.068
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发表时间：
2019
影响因子：
13.6
通讯作者：
Qu Yuanyuan
中科院分区：
文献类型：
--
作者：
Ma Qiao;Liu Ziyan;Yang Bingyu;Dai Chunxiao;Qu Yuanyuan
吲哚是一种常见的氮杂环污染物，也是广泛存在于各种环境基质中的信号分子。已有报道几种细菌菌株能够降解吲哚，但降解能力和功能酶的记录很少。本文对一株新分离的吲哚降解菌Burkholderiasp. IDO 3进行了仔细研究。菌株IDO 3在无机盐培养基中表现出良好的上级降解能力，可在14 h内完全去除100 mg/L的吲哚。在pH4.0 -9.0、温度25-35 ℃、转速0-250 r/min条件下，其降解性能相当，且大多数受试重金属和有机污染物对降解过程无显著影响。吲哚降解过程中发现了两个重要的中间产物靛红和邻氨基苯甲酸。利用基因组克隆文库技术和靛蓝筛选方法，成功地筛选出了功能基因。异源表达试验证明重组E.携带吲哚加氧酶和还原酶基因的大肠杆菌能将吲哚转化为靛蓝。生物信息学分析表明，新获得的酶IifC_IDO3形成了与其他相关芳香族加氧酶在遗传学上独立的分支。本研究为认识伯克霍尔德菌降解吲哚的机理提供了新的思路，也为吲哚的生物修复提供了有效的菌源。
Indole is a commonN-heterocyclic pollutant as well as a signaling molecule widespread in various environmental matrices. Several bacterial strains have been reported to be able to degrade indole, while the degradation capacity and functional enzymes are poorly documented. Herein, the degradation characteristics of a newly-isolated indole-degrading strainBurkholderiasp. IDO3 were carefully investigated. Strain IDO3 exhibited superior degradation ability which could completely remove 100 mg/L indole within 14 h in mineral salt medium. It maintained comparable degradation performance under conditions of pH 4.0–9.0, temperature 25–35 °C and rotary speed 0–250 r/min, and most of the tested heavy metals and organic pollutants did not significantly affect the degradation process. Two important intermediates, i.e. isatin and anthranilate, were identified in indole degradation process. The genomic clone library technique with indigo-based screening method was successfully applied to screen the functional genes. Heterologous expression assay proved that recombinantE. colistrain carrying indole oxygenase and reductase genesiifCDcould transform indole to indigo. Bioinformatic analyses indicated that the newly obtained enzyme IifC_IDO3 formed a phylogenetically separate branch from other related aromatic oxygenases. This study provides new insights into our understanding of indole degradation byBurkholderiastrains and offers efficient bacterial resource for indole bioremediation.