Structure and function of the microbial community in an in situ reactor to treat an acidic mine pit lake

Abstract

Sulfate-reducing bioreactors are a promising option for the treatment of acid mine drainage. We studied the structure and function of a biofilm in a methanol-fed fixed-bed in-lake reactor for the treatment of an acidic pit lake by a combination of laboratory incubations, chemical and molecular analyses and confocal laser scanning microscopy to determine whether competition by different groups of microorganisms as well as the precipitation of minerals affect reactor performance negatively. The biofilm growing on the surface of a synthetic carrier material consisted of dense microbial colonies covered by iron-sulfide precipitates. The microorganisms continuously had to overgrow this mineral coating, resulting in a high biomass turnover. About one third of the added methanol was used by sulfate reduction, and the rest by competing reactions. Sulfate-reducing bacteria as well as methanogens and acetogens were involved in methanol consumption. Six different groups of Deltaproteobacteria, dominated by the genera Desulfomonile, Desulfobacterium and a phylotype related to Geobacter, Gram-positive sulfate reducers of the genus Desulfosporosinus, acetogenic Acetobacteria, different fermenting bacteria as well as methylotrophic methanogens were identified. The versatility of the microbial food web is probably an important factor stabilizing the biofilm function under fluctuating and partly oxidizing conditions in the reactor.

Temporal evolution of bacterial communities associated with the in situ wetland-based remediation of a marine shore porphyry copper tailings deposit

“…and Desulfitobacterium spp. (Koschorreck et al, 2010;Johnson, 2012). As pH rises above 4, the diversity of sulfate-, but also Fe(III)-and Mn(IV)-reducing acidophilic bacteria increases with guild members of the δ-Proteobacteria (Desulfomonile spp., Desulfobacterium spp., Desulfosporosinus spp., Desulfitobacterium spp., and Geobacter spp.)…”

“…As pH rises above 4, the diversity of sulfate-, but also Fe(III)-and Mn(IV)-reducing acidophilic bacteria increases with guild members of the δ-Proteobacteria (Desulfomonile spp., Desulfobacterium spp., Desulfosporosinus spp., Desulfitobacterium spp., and Geobacter spp.) (Koschorreck et al, 2010;Burns et al, 2011;Sánchez-Andrea et al, 2013). Other lineages were also found, such as members of the phylum Nitrospirae (Thermodesulfovibrio spp.…”

Iron Transformations Induced by an Acid-Tolerant Desulfosporosinus Species

“…SRB activity in AMD-impacted systems is well documented (e.g., 4,14,21,22,27), but given the abundance of sulfate in these systems, surprisingly few acidophilic or acid-tolerant SRB have been recovered in culture (29). Strictly anaerobic SRB that have been isolated from AMD-impacted systems fall into the genus Desulfosporosinus (1,29,33,60), and representatives of this genus are frequently detected in anoxic regions of AMD-impacted systems (7,23,32,55,68). As such, Desulfosporosinus spp.…”

Characterization of the Bacterial and Sulphate Reducing Community in the Alkaline and Constantly Cold Water of the Closed Kotalahti Mine

“…In Ollinkuilu, the SRB contributed with 0.2% of the total microbial community at −70 and −100 m depth. These values are significantly lower than in recent studies, which have typically shown the clear dominance of sulphate reducers in the reactors treating sulphate and metal rich waters [35], also in in situ reactors [36] and at low temperatures (9 °C) [37]. However, it is plausible that the most effective sulphate reduction is taking place at the bottom of the pit at 800 m depth to where the organic substrates and sulphate reducers have sedimentated.…”