School of Minerals Processing and Bioengineering, Central South University, Changsha, 410083, China.
Key Laboratory of Biometallurgy, Ministry of Education, Changsha, 410083, China.
Bioprocess Biosyst Eng. 2020 Nov;43(11):1951-1960. doi: 10.1007/s00449-020-02384-8. Epub 2020 Jun 4.
In this study, the roles of extracellular polymeric substances (EPSs) excreted by Pandoraea sp. XY-2 in the removal of tetracycline (TC) were investigated. In the early stage, TC in the solution was mainly removed by the adsorption of EPSs, which accounted for 20% of TC. Thereafter, large amount of TC was transported into the intracellular and biodegraded. EPSs was extracted and the contents of polyprotein and polysaccharides reached their maximum values (30.84 mg/g and 11.15 mg/g) in the first four days. Fourier transform infrared spectroscopy analysis revealed that hydroxyl, methylidyne, methylene and amide I groups in EPSs participated in the adsorption of TC. Furthermore, three-dimensional excitation-emission matrix fluorescence spectroscopy analysis revealed that TC caused the quenching of EPSs fluorescent groups. The quenching mechanism was attributed to static quenching and protein-like substances in EPSs from Pandoraea sp. XY-2 dominated the TC adsorption process. Bioinformatic analysis of Pandoraea sp. XY-2 genome identified multiple genes involved in exopolysaccharide synthesis and EPSs formation. The insights gained in this study might provide a better understanding about the adsorption process of EPSs in tetracycline-contaminated environment.
在这项研究中，研究了 Pandoraea sp. XY-2 分泌的胞外聚合物（EPS）在去除四环素（TC）中的作用。在早期阶段，溶液中的 TC 主要通过 EPS 的吸附去除，占 TC 的 20%。此后，大量 TC 被转运到细胞内并被生物降解。在最初的四天内，EPS 被提取出来，其多糖和蛋白质的含量达到最大值（30.84mg/g 和 11.15mg/g）。傅里叶变换红外光谱分析表明，EPS 中的羟基、亚甲基、次甲基和酰胺 I 基团参与了 TC 的吸附。此外，三维激发-发射矩阵荧光光谱分析表明，TC 导致 EPSs 荧光团的猝灭。猝灭机制归因于静态猝灭，并且来自 Pandoraea sp. XY-2 的 EPSs 中的蛋白质样物质主导了 TC 的吸附过程。对 Pandoraea sp. XY-2 基因组的生物信息学分析鉴定了多个参与胞外多糖合成和 EPSs 形成的基因。本研究的结果可能有助于更好地理解 EPS 在四环素污染环境中的吸附过程。
