Removal of Arsenic Using Acid/Metal-Tolerant Sulfate Reducing Bacteria: A New Approach for Bioremediation of High-Arsenic Acid Mine Waters

Abstract

Fluvial sediments, soils, and natural waters in northern Chile are characterized by high arsenic (As) content. Mining operations in this area are potential sources of As and other metal contaminants, due to acid mine drainage (AMD) generation. Sulfate Reducing Bacteria (SRB) has been used for the treatment of AMD, as they allow for the reduction of sulfate, the generation of alkalinity, and the removal of dissolved heavy metals and metalloids by precipitation as insoluble metal sulfides. Thus, SRB could be used to remove As and other heavy metals from AMD, however the tolerance of SRB to high metal concentrations and low pH is limited. The present study aimed to quantify the impact of SRB in As removal under acidic and As-Fe-rich conditions. Our results show that SRB tolerate low pH (up to 3.5) and high concentrations of As (~3.6 mg·L −1 ). Batch experiments showed As removal of up to 73%, Iron (Fe) removal higher than 78% and a neutralization of pH from acidic to circum-neutral conditions (pH 6-8). In addition, XRD analysis showed the dominance of amorphous minerals, while Scanning Electron Microscopy/Energy Dispersive X-ray Spectroscopy (SEM-EDX) analysis showed associations between As, Fe, and sulfur, indicating the presence of Fe-S-As compounds or interaction of As species with amorphous and/or nanocrystalline phases by sorption processes. These results indicate that the As removal was mediated by acid/metal-tolerant SRB and open the potential for the application of new strains of acid/metal-tolerant SRB for the remediation of high-As acid mine waters.

Dynamics of Biocorrosion in Copper Pipes under Actual Drinking Water Conditions

“…The same increase trend was observed for the total alkalinity, from 51 to 219 mg/L as CaCO 3 , which increased to reach a plateau at the end of the study. The increase in total alkalinity and TOC over time can indicate possible contamination of the source water of the system by microbial growth [39]. This possibility is supported by the values of the sulfate, chloride, and nitrate levels, which were lower at the second sampling than those recorded at other times.…”

Alternative Strategies for Microbial Remediation of Pollutants via Synthetic Biology

“…Synthetic biology provides greater potential for the sustainable existence of microorganisms (Dellagnezze et al, 2014) acting together in a large population. Thus, synthetic microbial communities are proved as a key strategy for the bioremediation of contaminants, i.e., pesticides, petroleum (Kachienga et al, 2018), oil spill, acid drainage (Serrano and Leiva, 2017), etc. For building the synthetic microbial communities, the engineered interspecies and intraspecies interactions can make cellular functions robust and enhance the capabilities of microbial consortia in various contaminated scenarios.…”

DMSO Reductase Family: Phylogenetics and Applications of Extremophiles

“…Arsenic (As) is one of the most abundant and ubiquitous toxic heavy metals, and it occurs predominantly in the form of the inorganic oxyanions arsenate (H3AsO4) [As(V)] and arsenite (H3AsO3) [As(III)] [111]. Several groundwaters, sediments, and minerals are enriched in As, which can contaminate fluvial waters, affecting the quality of water resources thus limiting their use [112]. One of the most widely used pathways for the bioremediation of arsenic is the reduction of arsenate to arsenite through arsenate reductase.…”