The effect of extracellular polymeric substances (EPS) of iron-oxidizing bacteria (Ochrobactrum EEELCW01) on mineral transformation and arsenic (As) fate  

作　　者：Chuan Wu Yueru Chen Ziyan Qian Hongren Chen Waichin Li Qihou Li Shengguo Xue 

机构地区：[1]School of Metallurgy and Environment,Central South University,Changsha 410083,China [2]Department of Science and Environmental Studies,The Education University of Hong Kong,Hong Kong 999077,China [3]Ministry of Scientific Research,Central South University,Changsha 410083,China

出　　处：《Journal of Environmental Sciences》2023年第8期187-196,共10页环境科学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(No.42177392);the Dean’s Research Fund 2020/21(No.04626)of the Education University of Hong Kong.

摘　　要：Extracellular polymeric substances(EPS)are an importantmedium for communication and material exchange between iron-oxidizing bacteria and the external environment and could induce the iron(oxyhydr)oxides production which reduced arsenic(As)availability.The main component of EPS secreted by iron-oxidizing bacteria(Ochrobactrum EEELCW01)was composed of polysaccharides(150.76-165.33 mg/g DW)followed by considerably smaller amounts of proteins(12.98–16.12 mg/g DW).Low concentrations of As(100 or 500μmol/L)promoted the amount of EPS secretion.FTIR results showed that EPS was composed of polysaccharides,proteins,and a miniscule amount of nucleic acids.The functional groups including-COOH,-OH,-NH,-C=O,and-C-O played an important role in the adsorption of As.XPS results showed that As was bound to EPS in the form of As3+.With increasing As concentration,the proportion of As3+adsorbed on EPS increased.Ferrihydrite with a weak crystalline state was only produced in the system at 6 hr during the mineralization process of Ochrobactrum sp.At day 8,the minerals were composed of goethite,galena,and siderite.With the increasing mineralization time,the main mineral phases were transformed from weakly crystalline hydrous iron ore into higher crystallinity siderite(FeCO_(3))or goethite(α-FeOOH),and the specific surface area and active sites of minerals were reduced.It can be seen from the distribution of As elements that As is preferentially adsorbed on the edges of iron minerals.This study is potential to understand the biomineralizationmechanism of iron-oxidizing bacteria and As remediation in the environment.

关 键 词：Iron-oxidizing bacteria Extracellular polymeric substances (EPS) Arsenic(As) BIOMINERALIZATION Mineral phases transformation 

分 类 号：X172[环境科学与工程—环境科学]