An efficient phthalate ester-degrading Bacillus subtilis: Degradation kinetics, metabolic pathway, and catalytic mechanism of the key enzyme
An efficient phthalate ester-degrading Bacillus subtilis: Degradation kinetics, metabolic pathway, and catalytic mechanism of the key enzyme
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高效降解邻苯二甲酸酯的枯草芽孢杆菌：关键酶的降解动力学、代谢途径和催化机制
DOI：
10.1016/j.envpol.2021.116461
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发表时间：
2021
影响因子：
8.9
通讯作者：
Sun Baoguo
中科院分区：
文献类型：
--
作者：
Xu Youqiang;Liu Xiao;Zhao Jingrong;Huang Huiqin;Wu Mengqin;Li Xiuting;Li Weiwei;Sun Xiaotao;Sun Baoguo
环境和食物链中邻苯二甲酸酯污染的报道屡见不鲜。微生物处理是解决这一问题的绿色、高效的方法。对普遍认为安全的微生物（GRAS）的分离和系统研究将提供有用的资源。从白酒发酵剂中分离出一株枯草芽孢杆菌 BJQ0005，可有效降解邻苯二甲酸酯 (PAE)。邻苯二甲酸二异丁酯、邻苯二甲酸二丁酯和邻苯二甲酸二(2-乙基己基)酯的半衰期分别为 3.93、4.28 和 25.49 小时，起始量为每 10 mL 反应混合物 10 mg，这是使用野生型菌株记录的。基因组测序和代谢中间体分析生成了整个代谢途径。表达了 α/β 水解酶家族的 18 种酶。酶GTW28_09400和GTW28_13725能够水解PAE的单酯键，而GTW28_17760能够水解PAE的二酯键。利用分子对接，提出了GTW28_17760影响邻苯二甲酸单丁酯酶促酯键水解的可能机制。第一个水解步骤产生的羧基与催化活性中心的组氨酸相互作用，这对酶促水解产生负面影响。 B．PAE降解特性的分离和系统研究。 枯草芽孢杆菌将推动环境和食品行业PAEs的绿色、安全处理。
Phthalate ester pollution in the environment and food chain is frequently reported. Microbial treatment is a green and efficient method for solving this problem. The isolation and systematic investigation of microorganisms generally recognized as safe (GRAS) will provide useful resources. A GRASBacillus subtilisstrain, BJQ0005, was isolated from Baijiu fermentation starter and efficiently degraded phthalate esters (PAEs). The half-lives for di-isobutyl phthalate, di-butyl phthalate and di-(2-ethylhexyl) phthalate were 3.93, 4.28, and 25.49 h, respectively, from the initial amount of 10 mg per 10 mL reaction mixture, which are records using wild-type strains. Genome sequencing and metabolic intermediate analysis generated the whole metabolic pathway. Eighteen enzymes from the α/β hydrolase family were expressed. Enzymes GTW28_09400 and GTW28_13725 were capable of single ester bond hydrolysis of PAEs, while GTW28_17760 hydrolyzed di-ester bonds of PAEs. Using molecular docking, a possible mechanism affecting enzymatic ester bond hydrolysis of mono-butyl phthalate was proposed of GTW28_17760. The carboxyl group generated by the first hydrolysis step interacted with histidine in the catalytic active center, which negatively affected enzymatic hydrolysis. Isolation and systematic investigation of the PAE degradation characteristics ofB. subtiliswill promote the green and safe treatment of PAEs in the environment and food industry.