Effect of Organic Substrate on the Microbial Community Structure in Pilot-Scale Sulfate-Reducing Biochemical Reactors Treating Mine Drainage

Abstract

Passive biological systems such as sulfate-reducing biochemical reactors have shown promise for treatment of mine drainage because of their low cost, minimal maintenance, and constructability in remote locations. However, few criteria exist for their design and operation. In particular, the impact of the choice of carbon substrate is poorly understood. This study represents the first to directly compare the effect of simple and complex organic substrate on microbial communities present in pilot-scale biochemical reactors treating mine drainage. Three organic substrates were evaluated: ethanol (ETOH), hay and pine wood chips (HYWD), and corn stover and pine wood chips (CSWD). Microbial community compositions were characterized by cloning and sequencing of 16S rRNA and apsA genes corresponding to the sulfur cycle. Quantitative polymerase chain reaction was applied to quantify Desulfovibrio-Desulfomicrobium spp. and methanogens. Results revealed differences in microbial compositions and relative quantities of total and sulfate-reducing bacteria among reactors. Notably, the greatest proportion of sulfate-reducing bacteria was observed in the ETOH reactors. HYWD and CSWD reactors contained similar bacterial communities, which were highly complex in composition relative to the ETOH reactors. Methanogens were found to be present in all reactors at low levels and were highest in the lignocellulose-based reactors. Interestingly, higher proportions of aerobic Thiobacillus spp. were detected in two reactors that experienced an oxygen exposure during operation. This study demonstrates that both substrate and environmental stress influence both microbial community composition and diversity in biochemical reactors treating mine drainage. While there were no significant differences in performance observed over the time scale of this study, potential long-term implications of the differing microbial communities on performance are discussed.

Seasonal Microbial Population Shifts in a Bioremediation System Treating Metal and Sulfate-Rich Seepage

“…Minerals 2016, 6,36 October, January, March, April and July. These time points coincided with the peaks seen in the diversity metrics, and were grouped together in the principle co-ordinate analysis (Figure 2).…”

Spatial impacts of inorganic ligand availability and localized microbial community structure on mitigation of zinc laden mine water in sulfate-reducing bioreactors

“…With that in mind, it is important to note that the spatial homogeneity and controlled flow in a pilot-scale column system is not subject to the inherent variability encountered during field implementation. Preferential flow paths (Neculita et al, 2008), freeze-thaw cycles (Hiibel et al, 2011), plant colonization (Gusek and Schneider, 2010), and lateral variability are some of the factors affecting metal-sulfide precipitation in field SRBRs. Unfortunately, coring a field SRBR to query for spatial microbiology is challenging considering the heterogeneous mixture of limestone and organic materials, particles size distribution and saturated conditions present in SRBRs and the disruptive nature of draining that might be needed to obtain solid phase samples.…”

Study of the succession of microbial communities for sulfur cycle response to ecological factors change in sediment of sewage system

“…Thauera within beta-proteobacteria were important functional bacteria in the wastewater treatment system and were important in the denitrification process and in the carbon cycle. Fermenting bacteria and methanogens were also the important participant of carbon cycle in wastewater biochemical reaction process (Hiibel et al 2010). VFAs mainly produce by the fermenting bacteria in sewage which affected the sulfate reduction process significantly.…”