Microbial community analysis of two field‐scale sulfate‐reducing bioreactors treating mine drainage

Abstract

The microbial communities of two field-scale pilot sulfate-reducing bioreactors treating acid mine drainage (AMD), Luttrell and Peerless Jenny King (PJK), were compared using biomolecular tools and multivariate statistical analyses. The two bioreactors were well suited for this study because their geographic locations and substrate compositions were similar while the characteristics of influent AMD, configuration and degree of exposure to oxygen were distinct. The two bioreactor communities were found to be functionally similar, including cellulose degraders, fermenters and sulfate-reducing bacteria (SRB). Significant differences were found between the two bioreactors in phylogenetic comparisons of cloned 16S rRNA genes and adenosine 5'-phosphosulfate reductase (apsA) genes. The apsA gene clones from the Luttrell bioreactor were dominated by uncultured SRB most closely related to Desulfovibrio spp., while those of the PJK bioreactor were dominated by Thiobacillus spp. The fraction of the SRB genus Desulfovibrio was also higher at Luttrell than at PJK as determined by quantitative real-time polymerase chain reaction analysis. Oxygen exposure at PJK is hypothesized to be the primary cause of these differences. This study is the first rigorous phylogenetic investigation of field-scale bioreactors treating AMD and the first reported application of multivariate statistical analysis of remediation system microbial communities applying UniFrac software.

Iron Transformations Induced by an Acid-Tolerant Desulfosporosinus Species

“…Under conditions representative of AMD (i.e., initially low pH, high Fe concentrations), anaerobic microbial activities [i.e., Fe(III) and sulfate reduction] may lead to two major mineralogical (trans)formations: (i) the formation of the ferrimagnetic mineral phase greigite under conditions of high Fe(II):Fe(III) ratios and (ii) the transformation of schwertmannite to goethite. A goal of anaerobic AMD treatment systems (e.g., anoxic limestone drains) is to minimize Fe(III) formation, while precipitating Fe(II) and other metals as sulfide phases (4,8,27,22). In these Fe(III)-free systems, greigite may be an important product of SRB activities.…”

“…While anaerobic microbial activities (notably sulfate reduction) have been exploited for AMD remediation (4,8,22,27), in the context of iron mound systems, they may be considered detrimental to the overall goal of oxidatively precipitating Fe and maintaining the Fe(III) (hydr)oxide precipitates. The most abundant anaerobic terminal electron acceptors in AMD-impacted systems are sulfate and the Fe(III) (hydr)oxides.…”

“…For instance, most cultured acidophilic FeRB reduce Fe(III) optimally in the presence of O 2 (13). 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).…”

Interspecific interactions drive chitin and cellulose degradation by aquatic microorganisms

“…Furthermore, their decomposition is not a simple process, but there is no evidence of longterm accumulation of those substrates in aquatic ecosystems (Gooday 1990). This suggests complex and efficient degradation pathways involving a number of interactions (Mayor et al 2014), as demonstrated in decomposing wood (Borsodi et al 2005), sediments (Cardenas et al 2008), wetlands (Ibekwe et al 2003), and bioreactors (Hiibel et al 2008).…”

Advances in Passive Treatment of Coal Mine Drainage 1998-2009

“…They are therefore dependent on other microbes to break down cellulose and ferment it to simple compounds. In typical AMD treatment systems using organic matter, the SRB are a trace to minor component of the bacterial population (Logan et al, 2005;Hiibel et al, 2008). Most of the bacterial population is degrading cellulose and converting complex organics to simple organics that can be used by the SRB (Fig.…”