State Key Laboratory of Bioreactor Engineering, Biomedical Nanotechnology Center, Shanghai Collaborative Innovation Center for Biomanufacturing Technology, School of Biotechnology, East China University of Science and Technology, Shanghai 200237, China.
National Engineering Research Center for Biotechnology, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, China.
Int J Biol Macromol. 2019 Nov 1;140:1037-1046. doi: 10.1016/j.ijbiomac.2019.08.196. Epub 2019 Aug 23.
Azo dyes are the most widely applied chemical dyes that have also raised great concerns for environmental contamination and human health issues. There has been a growing interest in discovering bioremediation methods to degrade azo dyes for environmental and economic purposes. Azoreductases are key enzymes evolved in nature capable of degrading azo dyes. The current work reports the identification, expression, and properties of a novel azoreductase (AzoRed2) from Streptomyces sp. S27 which shows an excellent stability against pH change and organic solvents. To overcome the requirements of coenzyme while degrading azo dyes, we introduced a coenzyme regeneration enzyme, Bacillus subtilis glucose 1-dehydrogenase (BsGDH), to construct a recycling system in living cells. The whole-cell biocatalyst containing AzoRed2 and BsGDH was used to degrade a representative azo dye methyl red. The degradation rate of methyl red was up to 99% in 120 min with high substrate concentration (250 μM) and no external coenzyme added. The degradation rate was still 98% in the third batch trial. To sum up, a novel azoreductase with good properties was found, which was applied to construct whole-cell biocatalyst. Both the enzymes and whole-cell biocatalysts are good candidates for the industrial wastewater treatment and environmental restoration.
偶氮染料是应用最广泛的化学染料，但其对环境污染和人类健康问题也引起了极大的关注。人们越来越关注发现生物修复方法来降解偶氮染料，以达到环境和经济目的。偶氮还原酶是自然界中进化出来的关键酶，能够降解偶氮染料。目前的工作报道了从链霉菌 S27 中鉴定、表达和特性研究一种新型偶氮还原酶（AzoRed2），该酶对 pH 值变化和有机溶剂具有极好的稳定性。为了克服在降解偶氮染料时对辅酶的需求，我们引入了枯草芽孢杆菌葡萄糖 1-脱氢酶（BsGDH）作为辅酶再生酶，在活细胞中构建了一个循环系统。含有 AzoRed2 和 BsGDH 的全细胞生物催化剂被用于降解代表性的偶氮染料甲基红。在没有添加外部辅酶的情况下，在 120 分钟内，高浓度（250 μM）的甲基红的降解率达到 99%。在第三批试验中，降解率仍为 98%。总之，发现了一种具有良好性质的新型偶氮还原酶，并将其应用于构建全细胞生物催化剂。这两种酶和全细胞生物催化剂都是处理工业废水和环境修复的良好候选物。
