Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 510632, China.
Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 510632, China.
Bioresour Technol. 2019 Mar;276:119-126. doi: 10.1016/j.biortech.2018.12.100. Epub 2018 Dec 27.
Extracellular polymeric substances (EPS) play crucial roles in promoting biofilm formation and contribute to electrochemical activities of biofilms in bioelectrochemical systems (BES). In this study, three stratified EPS fractions were extracted from Geobacter biofilms using EDTA-, ultrasound- and heating-based protocols and characterized with chemical, spectral and electrochemical analyses. Results suggested that, for Geobacter biofilms, ultrasound-based extraction protocol was more effective in EPS yield (62.1-66.5 mg C/g dry cell) than EDTA method, and had less cell lysis than heating method. The extraction methods greatly affected the proteins composition in the extracted EPS, indicated by the varied ratios of tryptophan/tyrosine protein-like substances. Electrochemical measurements demonstrated a good correlation between protein concentration and extracellular electron transfer function for both tightly-bound EPS and total EPS. This is the first study to extract and characterize stratified EPS fractions from Geobacter biofilms, and helpful for better understanding the function of EPS in BESs predominated by Geobacter.
细胞外聚合物质（EPS）在促进生物膜形成方面发挥着关键作用，并有助于生物电化学系统（BES）中生物膜的电化学活性。在这项研究中，使用 EDTA、超声和加热基方案从 Geobacter 生物膜中提取了三种分层的 EPS 级分，并通过化学、光谱和电化学分析进行了表征。结果表明，对于 Geobacter 生物膜，超声提取方案比 EDTA 法更有效地提取 EPS（62.1-66.5mg C/g 干细胞），且细胞裂解程度低于加热法。提取方法极大地影响了提取的 EPS 中的蛋白质组成，这表明色氨酸/酪氨酸蛋白样物质的比值发生了变化。电化学测量表明，对于紧密结合的 EPS 和总 EPS，蛋白质浓度与细胞外电子传递功能之间存在良好的相关性。这是首次从 Geobacter 生物膜中提取和表征分层 EPS 级分的研究，有助于更好地理解 EPS 在以 Geobacter 为主的 BES 中的功能。
