College of Environmental Engineering, Nanjing Institute of Technology, Nanjing, 211167, China.
College of Environmental Engineering, Nanjing Institute of Technology, Nanjing, 211167, China; State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China.
Int J Biol Macromol. 2019 Feb 15;123:1062-1069. doi: 10.1016/j.ijbiomac.2018.11.175. Epub 2018 Nov 19.
Understanding the molecular mechanisms of azo dye decolorization is important for the development of effective bioremediation for textile-colored wastewater. A halophilic bacterium Halomonas sp. strain GT was isolated, which could degrade the azo dye Acid Brilliant Scarlet GR at 10% NaCl. The complete genome sequence of this strain was obtained using the PacBio RS II platform. Genome annotation revealed that four proteins are related to decolorization of azo dyes, such as azoreductase, laccases, benzene 1,2-dioxygenase, and catechol 1,2-dioxygenase. The putative azoreductase gene of Halomonas sp. strain GT responsible for the decolorization of azo dye in high salt environment was isolated. Phylogenetic tree analysis showed that the azoG (azoreductase gene of Halomonas sp. strain GT) and its homologs constituted a new branch of the NADH depending azoreductases, with all the homologous sequence of the protein from halophilic bacteria. At high NaCl concentrations, azoreductase gene expression and azoreductase activity were restrained in Halomonas sp. strain GT, which resulted in low a decolorization rate.
了解偶氮染料脱色的分子机制对于开发有效的纺织废水生物修复方法非常重要。本研究从 10%盐度的环境中分离到一株嗜盐菌 Halomonas sp. GT，该菌能够在 10%盐度下对偶氮染料酸性艳红 GR 进行脱色。利用 PacBio RS II 平台获得了该菌株的全基因组序列。基因组注释结果显示，有 4 种蛋白与偶氮染料的脱色有关，如偶氮还原酶、漆酶、苯 1,2-双加氧酶和儿茶酚 1,2-双加氧酶。本研究还分离到了一株嗜盐菌 GT 中负责在高盐环境下对偶氮染料进行脱色的假定偶氮还原酶基因。系统发育树分析表明，该基因及其同源基因构成了依赖 NADH 的偶氮还原酶的一个新分支，与所有来自嗜盐菌的蛋白的同源序列。在高 NaCl 浓度下，Halomonas sp. GT 中的偶氮还原酶基因表达和偶氮还原酶活性受到抑制，导致较低的脱色率。
