title: Importance of sulfide interaction with iron as regulator of the microbial community in biogas reactors and its effect on methanogenesis, volatile fatty acids turnover, and syntrophic long-chain fatty acids degradation.
abstract: The inhibitory effects of sulfide on microbial processes during anaerobic digestion have been widely addressed. However, other effects of sulfide are less explored, given that sulfide is a potential sulfur source for microorganisms and its high reactivity triggers a suit of abiotic reactions. We demonstrated that sulfide interaction with Fe regulates the dynamics and activities of microbial community during anaerobic digestion. This was manifested by the S:Fe molar ratio, whose increase adversely influenced the acetoclastic methanogens, Methanosaeta, and turnover of acetate. Dynamics of hydrogenotrophic methanogens, Methanoculleus and Methanobrevibacter, were presumably influenced by sulfide-induced changes in the partial pressure of hydrogen. Interestingly, conversion of the long-chain fatty acid (LCFA), oleate, to methane was enhanced together with the abundance of LCFA-degrading, β-oxidizing Syntrophomonas at an elevated S:Fe molar ratio. The results suggested that sulfur chemical speciation is a controlling factor for microbial community functions in anaerobic digestion processes.
authors.affiliation: Department of Thematic Studies-Environmental Change, Linköping University, 581 83 Linköping, Sweden; Biogas Research Center, Linköping University, 581 83 Linköping, Sweden. Electronic address: sepehr.shakeri.yekta@liu.se.
authors.forename: Sepehr
authors.initials: S
authors.lastname: Shakeri Yekta
authors.affiliation: Department of Civil and Environmental Engineering, University of Washington, Box 352700, Seattle, WA 98195, USA.
authors.forename: Ryan M
authors.initials: RM
authors.lastname: Ziels
authors.affiliation: Department of Thematic Studies-Environmental Change, Linköping University, 581 83 Linköping, Sweden; Biogas Research Center, Linköping University, 581 83 Linköping, Sweden.
authors.forename: Annika
authors.initials: A
authors.lastname: Björn
authors.affiliation: Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, 901 83 Umeå, Sweden.
authors.forename: Ulf
authors.initials: U
authors.lastname: Skyllberg
authors.affiliation: Department of Thematic Studies-Environmental Change, Linköping University, 581 83 Linköping, Sweden; Scandinavian Biogas Fuels AB, 111 60 Stockholm, Sweden; Biogas Research Center, Linköping University, 581 83 Linköping, Sweden.
authors.forename: Jörgen
authors.initials: J
authors.lastname: Ejlertsson
authors.affiliation: Scandinavian Biogas Fuels AB, 111 60 Stockholm, Sweden; Biogas Research Center, Linköping University, 581 83 Linköping, Sweden.
authors.forename: Anna
authors.initials: A
authors.lastname: Karlsson
authors.affiliation: Department of Thematic Studies-Environmental Change, Linköping University, 581 83 Linköping, Sweden; Scandinavian Biogas Fuels AB, 111 60 Stockholm, Sweden.
authors.forename: Matilda
authors.initials: M
authors.lastname: Svedlund
authors.affiliation: Department of Thematic Studies-Environmental Change, Linköping University, 581 83 Linköping, Sweden.
authors.forename: Magnus
authors.initials: M
authors.lastname: Willén
authors.affiliation: Department of Thematic Studies-Environmental Change, Linköping University, 581 83 Linköping, Sweden; Biogas Research Center, Linköping University, 581 83 Linköping, Sweden.
authors.forename: Bo H
authors.initials: BH
authors.lastname: Svensson
mesh_terms: D000085:Acetates / Q000378:metabolism; D000693:Anaerobiosis; D001421:Bacteria, Anaerobic / Q000378:metabolism; D056804:Biofuels; D019149:Bioreactors / Q000382:microbiology*; D000068016:Eubacteriales / Q000378:metabolism; D005232:Fatty Acids, Volatile / Q000378:metabolism*; D006859:Hydrogen / Q000378:metabolism; D007501:Iron / Q000378:metabolism*; D008697:Methane / Q000096:biosynthesis*; D041581:Methanobrevibacter / Q000378:metabolism; D019638:Methanomicrobiaceae / Q000378:metabolism; D019640:Methanosarcinales / Q000378:metabolism; D019301:Oleic Acid / Q000737:chemistry / Q000378:metabolism; D010084:Oxidation-Reduction; D013440:Sulfides / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000085:Acetates; D056804:Biofuels; D005232:Fatty Acids, Volatile; D013440:Sulfides; D019301:Oleic Acid; D006859:Hydrogen; D007501:Iron; D008697:Methane
keywords: Anaerobic digestion; Iron; Microbial community; Sewage sludge; Sulfide