title: The microbial community of a passive biochemical reactor treating arsenic, zinc, and sulfate-rich seepage.
abstract: Sulfidogenic biochemical reactors (BCRs) for metal removal that use complex organic carbon have been shown to be effective in laboratory studies, but their performance in the field is highly variable. Successful operation depends on the types of microorganisms supported by the organic matrix, and factors affecting the community composition are unknown. A molecular survey of a field-based BCR that had been removing zinc and arsenic for over 6 years revealed that the microbial community was dominated by methanogens related to Methanocorpusculum sp. and Methanosarcina sp., which co-occurred with Bacteroidetes environmental groups, such as Vadin HA17, in places where the organic matter was more degraded. The metabolic potential for organic matter decomposition by Ruminococcaceae was prevalent in samples with more pyrolyzable carbon. Rhodobium- and Hyphomicrobium-related genera within the Rhizobiales order that have the metabolic potential for dark hydrogen fermentation and methylotrophy, and unclassified Comamonadaceae were the dominant Proteobacteria. The unclassified environmental group Sh765B-TzT-29 was an important Delta-Proteobacteria group in this BCR that co-occurred with the dominant Rhizobiales operational taxonomic units. Organic matter degradation is one driver for shifting the microbial community composition and therefore possibly the performance of these bioreactors over time.
authors: Chemical and Biological Engineering, University of British Columbia , Vancouver, BC , Canada.
authors: Susan Anne
authors: SA
authors: Baldwin
authors: Chemical and Biological Engineering, University of British Columbia , Vancouver, BC , Canada.
authors: Maryam
authors: M
authors: Khoshnoodi
authors: Chemical and Biological Engineering, University of British Columbia , Vancouver, BC , Canada.
authors: Maryam
authors: M
authors: Rezadehbashi
authors: Department of Microbiology and Immunology, University of British Columbia , Vancouver, BC , Canada.
authors: Marcus
authors: M
authors: Taupp
authors: Department of Microbiology and Immunology, University of British Columbia , Vancouver, BC , Canada.
authors: Steven
authors: S
authors: Hallam
authors: NatureWorks Remediation Corporation , Rossland, BC , Canada.
authors: Al
authors: A
authors: Mattes
authors: Geological Survey of Canada , Calgary, AB , Canada ; Center for Energy Technologies (CET), AU-Herning, Aarhus University , Herning , Denmark ; Department of Geoscience, University of Calgary , Calgary, AB , Canada.
authors: Hamed
authors: H
authors: Sanei
keywords: Rock-Eval-6; biochemical reactor; bioremediation; metals; microbial ecology; organic matter degradation; sequencing; water treatment