Gordonia sp.QH-11对邻苯二甲酸酯的关键生物降解机制研究

Phthalate esters (PAEs) are an important group of environmental hormones, and have become ubiquitous environmental pollutants, microbial degradation is a key elimination pathway of PAEs from various environmental conditions. However, the fact that many bacterial strains can only transform PAEs to phthalic acid (PA) need to be paid more attentions. In 2012, the Gordonia sp. (designated as QH-11) which can degrade both PAEs and PA simultaneously was reported in our research group. Based on the obtained experimental data and difficult issues in PAEs biodegradation by Gordonia sp., dibutyl phthalate (DBP) is selected as a representative endocrine disruptor in this project, and DBP esterase and monobutyl phthalate (MBP) hydrolase will be cloned according to complete genome analysis, and then studies on expression, optimization, and purification of recombinant proteins in E. coli BL21(DE3) and their activity and substrate specificity analysis will be performed. In additional, PA degradation gene cluster will also be cloned and functionally verified. This project findings will be of great value for understanding the genetic mechanisms of biodegradation of PAEs by Gordonia sp. and functional diversity of Gordonia strains and will also provide a theoretical basis for the in-situ bioremediation of PAEs.

邻苯二甲酸酯类化合物（Phthalate esters, PAEs）是一类广泛存在的环境激素类污染物，生物降解是其在环境中去除的主要途径，然而大多菌株只能将PAEs最终降解成邻苯二甲酸（Phthalic acid, PA）。申请人研究组于2012年报道了一株能同时降解PAEs和PA的Gordonia细菌（QH-11），基于前期研究基础及该属PAEs生物降解中亟待解决的难点问题 ，拟以邻苯二甲酸二丁酯（Dibutyl phthalate, DBP）为PAEs模式污染物，克隆菌株QH-11中的DBP酯酶，邻苯二甲酸单丁酯（Monobutyl phthalate, MBP）水解酶并进行异源表达，纯化重组蛋白开展其酶活及降解底物特异性研究；同时克隆PA降解基因簇并验证其功能。本研究预期为Gordonia细菌PAEs生物降解遗传机制、功能多样性及PAEs污染场地的微生物治理提供理论支持和技术储备。

邻苯二甲酸酯类化合物（Phthalate esters, PAEs）是一类广泛存在的环境激素类污染物，生物降解是其在环境中去除的主要途径。本项目以PAEs完全降解菌Gordonia sp. QH-11为研究对象，通过基因组分析，克隆了菌株QH-11中的DBP酯酶并成功异源表达，该酶为PAEs生物降解过程中的关键酶及第一步反应酶。同时，确定了菌株QH-11为国际分类学细菌新种，命名为Gordonia phthalatica sp. QH-11T。发现了DBP污染能够显著影响土壤-植物系统的微生物生态功能，具有一定的农田蔬菜食品安全风险，利用QH-11微生物菌剂能够在蔬菜根际阻断塑化剂的污染，消减蔬菜体内的塑化剂含量。本研究能够为Gordonia细菌PAEs生物降解遗传机制、功能多样性及PAEs农田污染的微生物治理提供理论支持和技术储备。