Profiling Microbial Communities in Manganese Remediation Systems Treating Coal Mine Drainage

Abstract

cWater discharging from abandoned coal mines can contain extremely high manganese levels. Removing this metal is an ongoing challenge. Passive Mn(II) removal beds (MRBs) contain microorganisms that oxidize soluble Mn(II) to insoluble Mn(III/IV) minerals, but system performance is unpredictable. Using amplicon pyrosequencing, we profiled the bacterial, fungal, algal, and archaeal communities in four MRBs, performing at different levels, in Pennsylvania to determine whether they differed among MRBs and from surrounding soil and to establish the relative abundance of known Mn(II) oxidizers. Archaea were not detected; PCRs with archaeal primers returned only nontarget bacterial sequences. Fungal taxonomic profiles differed starkly between sites that remove the majority of influent Mn and those that do not, with the former being dominated by Ascomycota (mostly Dothideomycetes) and the latter by Basidiomycota (almost entirely Agaricomycetes). Taxonomic profiles for the other groups did not differ significantly between MRBs, but operational taxonomic unit-based analyses showed significant clustering by MRB with all three groups (P < 0.05). Soil samples clustered separately from MRBs in all groups except fungi, whose soil samples clustered loosely with their respective MRB. Known Mn(II) oxidizers accounted for a minor proportion of bacterial sequences (up to 0.20%) but a greater proportion of fungal sequences (up to 14.78%). MRB communities are more diverse than previously thought, and more organisms may be capable of Mn(II) oxidation than are currently known.

Nutrient input influences fungal community composition and size and can stimulate manganese (II) oxidation in caves

“…Also of relevance, a recent study by Chaput et al . () demonstrated that Ascoymcete fungi were more prevalent than Basidiomycota (largely Agaricomycetes) in passive remediation systems that were most effective in treating high concentrations of dissolved Mn emanating from abandoned coal mines. Although the Chaput et al .…”

Fungal Iron Biomineralization in Río Tinto

“…All major microbial groups are capable of immobilizing metal ions and carrying out mineralization processes through organic and inorganic precipitation of secondary associated minerals as well as depositing crystalline material on and within cell walls [31,34,35]. Also, fungi have been reported as an important part of the microbial community of Río Tinto, as well as other mine drainage systems with similar characteristics (e.g., [7,[36][37][38]) So, in a scenario like Río Tinto, it is not unreasonable that fungi may be involved in different geochemical cycles, such as the dissolution of certain minerals and the formation of new ones.…”

“…Río Tinto, as well as other mine drainage systems with similar characteristics (e.g., [7,[36][37][38]) So, in a scenario like Río Tinto, it is not unreasonable that fungi may be involved in different geochemical cycles, such as the dissolution of certain minerals and the formation of new ones. Our TEM and HAADF-STEM analyses of the M13 sediments showed fungal cells involved in biomineralization processes with minerals nucleated on fungal cell walls (Figure 4).…”

Mine Drainage Generation and Control Options

“…Coal gangue, sandy soil, and clay (mass ratio 45:4:1) as goaf filling materials were investigated as an effective treatment method for the removal of Fe and Mn from mining drainage (Zhang et al, 2015). Experiments Pennsylvania (Chaput et al, 2015). The goal was to determine whether the communities differed among MRBs and the surrounding soil as well as establish the relative abundance of known Mn(II) oxidizers.…”