Anxu Sheng , Yurong Deng , Yuefei Ding , Linxin Cheng , Yuyan Liu , Xiaoxu Li , Yuji Arai , Juan Liu
{"title":"铁(II)供应率和细胞外聚合物质对铁酸盐生物转化的调节作用","authors":"Anxu Sheng , Yurong Deng , Yuefei Ding , Linxin Cheng , Yuyan Liu , Xiaoxu Li , Yuji Arai , Juan Liu","doi":"10.1016/j.gca.2024.08.029","DOIUrl":null,"url":null,"abstract":"<div><div>Biotransformation of ferrihydrite (Fh) by dissimilatory iron-reducing bacteria (DIRB) into various secondary minerals assemblages widely occurs in anaerobic environments. While respiration-driven supply rates of Fe(II) have been proposed as a primary factor controlling kinetics and mineral products of this process, the specific mechanism by which DIRB respiration rates regulate Fh biotransformation remains elusive. Here, to minimize the complex effects of microbial cells, we conducted Fh transformation using 1 mM biogenic Fe(II) (BioFe(II)), added at different rates to mimic diverse respiration-driven supply rates of Fe(II) by DIRB. For comparison, transformation experiments with FeSO<sub>4</sub> alone and FeSO<sub>4</sub> plus citrate (CitFe(II)) added at the corresponding supply rates were performed to decouple the specific effects of Fe(II) addition rates and extracellular polymeric substances (EPS) associated with BioFe(II). Decreasing FeSO<sub>4</sub> supply rates favored the transformation of Fh to lepidocrocite (Lp) over to Gt and the subsequent transformation of Lp to magnetite (Mt), altering the transformation pathway from Fh → Lp/Gt → Gt to Fh → Lp/Gt → Mt/Gt. These results underscore the significant effect of aqueous Fe(II) supply rates on the competition of olation and oxolation of labile Fe(III) intermediates into different secondary minerals. In the experiments with BioFe(II) and CitFe(II), although EPS or citrate slightly increased Fe(II) adsorption and Fe(III)<sub>labile</sub> generation, the increase in sorbed Fe(II) was minimal compared to the variations in aqueous Fe(II) concentrations caused by the different Fe(II) supply rates. At the same Fe(II) supply rates, EPS or citrate notably inhibited the transformation of Fh to Gt and the further conversion of Lp, altering the pathway from Fh → Mt/Gt/Lp to primarily Fh → Lp. These effects became more pronounced with the decrease of BioFe(II) and CitFe(II) supply rates. Our findings provide new insights into how DIRB respiration rates control kinetics, pathways, and mineral products of Fh transformation, which is crucial for elucidating the relevant biogeochemical cycling of nutrients and (im)mobilization of contaminants.</div></div>","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"385 ","pages":"Pages 87-99"},"PeriodicalIF":4.5000,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Regulation of ferrihydrite biotransformation by Fe(II) supply rates and extracellular polymeric substances\",\"authors\":\"Anxu Sheng , Yurong Deng , Yuefei Ding , Linxin Cheng , Yuyan Liu , Xiaoxu Li , Yuji Arai , Juan Liu\",\"doi\":\"10.1016/j.gca.2024.08.029\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>Biotransformation of ferrihydrite (Fh) by dissimilatory iron-reducing bacteria (DIRB) into various secondary minerals assemblages widely occurs in anaerobic environments. While respiration-driven supply rates of Fe(II) have been proposed as a primary factor controlling kinetics and mineral products of this process, the specific mechanism by which DIRB respiration rates regulate Fh biotransformation remains elusive. Here, to minimize the complex effects of microbial cells, we conducted Fh transformation using 1 mM biogenic Fe(II) (BioFe(II)), added at different rates to mimic diverse respiration-driven supply rates of Fe(II) by DIRB. For comparison, transformation experiments with FeSO<sub>4</sub> alone and FeSO<sub>4</sub> plus citrate (CitFe(II)) added at the corresponding supply rates were performed to decouple the specific effects of Fe(II) addition rates and extracellular polymeric substances (EPS) associated with BioFe(II). Decreasing FeSO<sub>4</sub> supply rates favored the transformation of Fh to lepidocrocite (Lp) over to Gt and the subsequent transformation of Lp to magnetite (Mt), altering the transformation pathway from Fh → Lp/Gt → Gt to Fh → Lp/Gt → Mt/Gt. These results underscore the significant effect of aqueous Fe(II) supply rates on the competition of olation and oxolation of labile Fe(III) intermediates into different secondary minerals. In the experiments with BioFe(II) and CitFe(II), although EPS or citrate slightly increased Fe(II) adsorption and Fe(III)<sub>labile</sub> generation, the increase in sorbed Fe(II) was minimal compared to the variations in aqueous Fe(II) concentrations caused by the different Fe(II) supply rates. At the same Fe(II) supply rates, EPS or citrate notably inhibited the transformation of Fh to Gt and the further conversion of Lp, altering the pathway from Fh → Mt/Gt/Lp to primarily Fh → Lp. These effects became more pronounced with the decrease of BioFe(II) and CitFe(II) supply rates. Our findings provide new insights into how DIRB respiration rates control kinetics, pathways, and mineral products of Fh transformation, which is crucial for elucidating the relevant biogeochemical cycling of nutrients and (im)mobilization of contaminants.</div></div>\",\"PeriodicalId\":327,\"journal\":{\"name\":\"Geochimica et Cosmochimica Acta\",\"volume\":\"385 \",\"pages\":\"Pages 87-99\"},\"PeriodicalIF\":4.5000,\"publicationDate\":\"2024-09-04\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Geochimica et Cosmochimica Acta\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0016703724004356\",\"RegionNum\":1,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"GEOCHEMISTRY & GEOPHYSICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Geochimica et Cosmochimica Acta","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0016703724004356","RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"GEOCHEMISTRY & GEOPHYSICS","Score":null,"Total":0}
Regulation of ferrihydrite biotransformation by Fe(II) supply rates and extracellular polymeric substances
Biotransformation of ferrihydrite (Fh) by dissimilatory iron-reducing bacteria (DIRB) into various secondary minerals assemblages widely occurs in anaerobic environments. While respiration-driven supply rates of Fe(II) have been proposed as a primary factor controlling kinetics and mineral products of this process, the specific mechanism by which DIRB respiration rates regulate Fh biotransformation remains elusive. Here, to minimize the complex effects of microbial cells, we conducted Fh transformation using 1 mM biogenic Fe(II) (BioFe(II)), added at different rates to mimic diverse respiration-driven supply rates of Fe(II) by DIRB. For comparison, transformation experiments with FeSO4 alone and FeSO4 plus citrate (CitFe(II)) added at the corresponding supply rates were performed to decouple the specific effects of Fe(II) addition rates and extracellular polymeric substances (EPS) associated with BioFe(II). Decreasing FeSO4 supply rates favored the transformation of Fh to lepidocrocite (Lp) over to Gt and the subsequent transformation of Lp to magnetite (Mt), altering the transformation pathway from Fh → Lp/Gt → Gt to Fh → Lp/Gt → Mt/Gt. These results underscore the significant effect of aqueous Fe(II) supply rates on the competition of olation and oxolation of labile Fe(III) intermediates into different secondary minerals. In the experiments with BioFe(II) and CitFe(II), although EPS or citrate slightly increased Fe(II) adsorption and Fe(III)labile generation, the increase in sorbed Fe(II) was minimal compared to the variations in aqueous Fe(II) concentrations caused by the different Fe(II) supply rates. At the same Fe(II) supply rates, EPS or citrate notably inhibited the transformation of Fh to Gt and the further conversion of Lp, altering the pathway from Fh → Mt/Gt/Lp to primarily Fh → Lp. These effects became more pronounced with the decrease of BioFe(II) and CitFe(II) supply rates. Our findings provide new insights into how DIRB respiration rates control kinetics, pathways, and mineral products of Fh transformation, which is crucial for elucidating the relevant biogeochemical cycling of nutrients and (im)mobilization of contaminants.
期刊介绍:
Geochimica et Cosmochimica Acta publishes research papers in a wide range of subjects in terrestrial geochemistry, meteoritics, and planetary geochemistry. The scope of the journal includes:
1). Physical chemistry of gases, aqueous solutions, glasses, and crystalline solids
2). Igneous and metamorphic petrology
3). Chemical processes in the atmosphere, hydrosphere, biosphere, and lithosphere of the Earth
4). Organic geochemistry
5). Isotope geochemistry
6). Meteoritics and meteorite impacts
7). Lunar science; and
8). Planetary geochemistry.