Spontaneous assembly of microbial extracellular polymeric substances into microcapsules involved in trapping and immobilizing degradation-resistant oxoanions.
Spontaneous assembly of microbial extracellular polymeric substances into microcapsules involved in trapping and immobilizing degradation-resistant oxoanions.
复制标题
DOI：
10.1016/j.scitotenv.2020.143651
复制
发表时间：
2020-11
期刊：
影响因子：
--
通讯作者：
Qian Wang;Kai Chen;Shuhan Huang;Xuezhu Zhu;Fuxing Kang
中科院分区：
文献类型：
--
作者：
Qian Wang;Kai Chen;Shuhan Huang;Xuezhu Zhu;Fuxing Kang
Despite the ubiquity of microbial extracellular polymeric substances (EPS) in soils and aquatic environments, the roles played by EPS in the nonreductive transformation of toxic and degradation-resistant oxoanions are poorly understood. Here, we used perchlorate, which is ubiquitous in surface environments, as an initiator to study the spontaneous assembly of EPS into microcapsules involved in trapping and immobilizing oxoanions. The results confirmed that ClO4−oxoanions could be rapidly trapped in 20 min by EPS extracted from a common Bacillus subtilis, whereas no chemical reduction of ClO4−occurred in 48 h. Integrated spectroscopic analyses with florescence quenching microtitration and theoretical models showed that amino functionalities of EPS are responsible for sequestering ClO4−, with lower pH values being more favorable to formation of EPS-ClO4−micelles. Combined molecular dynamics scheme with wave function analyses showed that besides amino residues, the protonated side-chain amino groups in the basic proteins have a greater capacity for sequestering ClO4−through a noncovalent H-bonding mechanism in which dissociable protons serve as the nodes to bridge ClO4−. A quantitative association between the number of hydrogen bonds and bioavailability revealed that immobilization by EPS mitigates the uptake of toxic oxoanions by forage ryegrass, reducing their risk exposure to edible produce.Main finding of the workMicelles formed by freely dissolved EPS mitigate the uptake of toxic oxoanions by forage ryegrass
