Biogeochemical fate of ferrihydrite-model organic compound complexes during anaerobic microbial reduction

Dawit N Wordofa; Dinesh Adhikari; Sarrah M Dunham-Cheatham; Qian Zhao; Simon R Poulson; Yuanzhi Tang; Yu Yang

doi:10.1016/j.scitotenv.2019.02.441

Biogeochemical fate of ferrihydrite-model organic compound complexes during anaerobic microbial reduction

Sci Total Environ. 2019 Jun 10:668:216-223. doi: 10.1016/j.scitotenv.2019.02.441. Epub 2019 Mar 1.

Authors

Dawit N Wordofa¹, Dinesh Adhikari¹, Sarrah M Dunham-Cheatham², Qian Zhao³, Simon R Poulson⁴, Yuanzhi Tang⁵, Yu Yang⁶

Affiliations

¹ Department of Civil and Environmental Engineering, University of Nevada, Reno, NV 89557, USA.
² Department of Civil and Environmental Engineering, University of Nevada, Reno, NV 89557, USA; Department of Natural Resources and Environmental Science, University of Nevada, Reno, NV 89557, USA.
³ Department of Civil and Environmental Engineering, University of Nevada, Reno, NV 89557, USA; Pacific Northwest National Laboratory, Richland, WA 99354, USA.
⁴ Department of Geological Sciences and Engineering, University of Nevada, Reno, NV 89557, USA.
⁵ School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA.
⁶ Department of Civil and Environmental Engineering, University of Nevada, Reno, NV 89557, USA. Electronic address: yuy@unr.edu.

PMID: 30852198
DOI: 10.1016/j.scitotenv.2019.02.441

Abstract

Associations of organic carbon (OC) with iron (Fe) oxide minerals play an important role in regulating the stability of OC in soil environments. Knowledge about the fate and stability of Fe-OC complexes is impaired by the heterogeneity of OC. Additional biogeochemical variables in soil environments, such as redox conditions and microbes, further increase complexity in understanding the stability of mineral-associated soil OC. This study investigated the fate and stability of model organic compounds, including glucose (GL), glucosamine (GN), tyrosine (TN), benzoquinone (BQ), amylose (AM), and alginate (AL), complexed with an Fe oxide mineral, ferrihydrite (Fh), during microbial reduction. During a 25-d anaerobic incubation with Shewanella putrefaciens CN32, the reduction of Fe followed the order of Fh-BQ > Fh-GL > Fh-GN > Fh-TN > Fh-AL > Fh-AM. In terms of OC released during the anaerobic incubation, Fh-GN complexes released the highest amount of OC while Fh-AM complexes released the lowest. Organic carbon regulated the reduction of Fe by acting as an electron shuttle, affecting microbial activities, and associating with Fh. Benzoquinone had the highest electron accepting capacity, but potentially can inhibit microbial activity. These findings provide insights into the roles of different organic functional groups in regulating Fe reduction and the stability of Fh-bound OC under anaerobic conditions.

Keywords: Electron transport; Ferrihydrite; Microbial reduction; Organic carbon; Quinone.

MeSH terms

Anaerobiosis
Ferric Compounds / metabolism*
Models, Chemical*
Organic Chemicals / metabolism*

Substances

Ferric Compounds
Organic Chemicals
ferric oxyhydroxide