张珈瑜,彭星星,贾晓珊.磺胺二甲基嘧啶(SM2)高效降解菌J2的分离筛选及降解特性研究[J].环境科学学报,2019,39(9):2919-2927
磺胺二甲基嘧啶(SM2)高效降解菌J2的分离筛选及降解特性研究
- Isolation and characterization of highly efficient sulfamethazine-degrading bacterium strain J2
- 基金项目：国家自然科学基金（No.20183800041030649）；广东省科技计划粤港联合创新项目（No.20163800042410510）
- 张珈瑜
- 1. 中山大学环境科学与工程学院, 广州 510275;2. 广东省环境污染控制与修复技术重点实验室, 广州 510275
- 彭星星
- 1. 中山大学环境科学与工程学院, 广州 510275;2. 广东省环境污染控制与修复技术重点实验室, 广州 510275
- 贾晓珊
- 1. 中山大学环境科学与工程学院, 广州 510275;2. 广东省环境污染控制与修复技术重点实验室, 广州 510275
- 摘要：从城市污水处理厂活性污泥中分离得到一株能以磺胺二甲基嘧啶（SM2）为唯一碳源的菌株，经生理生化鉴定和16S rRNA基因序列同源性分析，将此菌鉴定为蜡样芽孢杆菌（Bacillus cereus），命名为J2.不同条件下的降解特性研究结果表明，J2菌株具有极高的SM2耐受性（100 mg·L-1）、较广的温度（20~30℃）和pH （6~8）适用范围；在温度30℃、pH=8.0、初始OD600=0.1、SM2起始浓度为50 mg·L-1的条件下，J2菌株在36 h内对SM2的降解率可达100%，降解效率远超目前已报道的其他SM2降解菌株，展现出了良好的应用潜力.J2菌株降解SM2过程中产生了5种主要中间代谢产物，分析推断其降解SM2的途径分为两条：①磺胺二甲基嘧啶分子首先在酶促反应作用下脱除SO2，生成嘧啶环和苯胺环自由基，这两种自由基再经过环间耦合生成N-（4，6-二甲基嘧啶-2基）-1，4-二苯胺，该分子中的C—N键在活性氧物种的作用下断开生成苯胺和2-氨基-4，6-二甲基嘧啶；②在漆酶的作用下N4键断裂，产生N-（3，5-二甲基嘧啶）-苯磺酰胺，之后N-（3，5-二甲基嘧啶）-苯磺酰胺的N—S键断裂，进一步形成2-氨基-4，6-二甲基嘧啶和苯亚砜.
- Abstract：In the present study, a bacterial strain isolated from the activated sludge of an urban wastewater treatment plant was employed to degrade sulfamethazine. According to the phenotype, physiological, biochemical analyses and 16S rRNA sequence analysis, the strain was preliminary identified as Bacillus cereus and designated as J2. J2 has high SM2 tolerance (100 mg·L-1), the broad temperature (20~30 ℃) and pH (6~8) adaptability. Results show that 50 mg·L-1 SM2 was completely degraded in 36 h at 30 ℃, pH 7.0 with OD600 at 0.1. J2 also exhibits higher tolerance and degradation efficiency than other SM2-degrading strains. Five intermediates were identified by LC-MS/MS analysis, two probable degradation pathways of SM2 by J2 was tentatively proposed: ①SO2 was firstly removed from the SM2 molecules under the action of enzymatic reaction to generate pyrimidine and aniline radicals and then N-(4,6-dimethylpyrimidine-2)-1,4-diphenylamine was generated through ring coupling reaction between the two radicals, and the C—N bond subsequently broke off to the form phenylamine and 2-amino-4,6-dimethylpyrimidine by the attack of reactive oxygen species. ②The N4 bond was broken through the action of laccase, producing N-(4-hydrosulfonylphenyl)-3,5-dimethylaniline, and then the N—S bond was broken to form 2-amino-4,6-dimethylpyrimidine and hydrosulfonylbenzene.
