Vivianite is often found in reducing environments rich in iron and phosphorus from organic debris degradation or phosphorus mineral dissolution.The formation of vivianite is essen-tial to the geochemical cycling of phosphorus and iron elements in natural environments.In this study,extracellular polymeric substances(EPS)were selected as the source of phospho-rus.Microcosm experiments were conducted to test the evolution of mineralogy during the reduction of polyferric sulfate flocs(PFS)by Shewanella oneidensis MR-1(S.oneidensis MR-1)at EPS concentrations of 0,0.03,and 0.3 g/L.Vivianite was found to be the secondary mineral in EPS treatment when there was no phosphate in the media.The EPS DNA served as the phosphorus source and DNA-supplied phosphate could induce the formation of vivianite.EPS impedes PFS aggregation,contains redox proteins and stores electron shuttle,and thus greatly promotes the formation of minerals and enhances the reduction of Fe(Ⅲ).At EPS concentration of 0,0.03,and 0.3 g/L,the produced HCl-extractable Fe(Ⅱ)was 107.9,111.0,and 115.2 mg/L,respectively.However,when the microcosms remained unstirred,vivianite can be formed without the addition of EPS.In unstirred systems,the EPS secreted by S.onei-densis MR-1 could agglomerate at some areas,resulting in the formation of vivianite in the proximity of microbial cells.It was found that vivianite can be generated biogenetically by S.oneidensis MR-1 strain and EPS may play a key role in iron reduction and concentrating phosphorus in the oligotrophic ecosystems where quiescent conditions prevail.

School of Environment and Energy,South China University of Technology,Guangzhou 510006,China;The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters,Ministry of Education,South China University of Technology,Guangzhou 510006,China;Department of Environmental Science,Rutgers University,New Brunswick,NJ 08901,USA

[1]Xinrui Hao;Jie Tang;Xiaoyun Yi;Kun Gao;Qian Yao;Chunhua Feng;Weilin Huang;Zhi Dang-.Extracellular polymeric substance induces biogenesis of vivianite under inorganic phosphate-free conditions)[J].环境科学学报（英文版）,2022(10):115-124

vivianite,Vivianite,Microcosm,polyferric,microcosms,unstirred,onei,densis,biogenetically

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