Microbial communities in acid mine drainage

Abstract

The dissolution of sulfide minerals such as pyrite (FeS2), arsenopyrite (FeAsS), chalcopyrite (CuFeS2), sphalerite (ZnS), and marcasite (FeS2) yields hot, sulfuric acid-rich solutions that contain high concentrations of toxic metals. In locations where access of oxidants to sulfide mineral surfaces is increased by mining, the resulting acid mine drainage (AMD) may contaminate surrounding ecosystems. Communities of autotrophic and heterotrophic archaea and bacteria catalyze iron and sulfur oxidation, thus may ultimately determine the rate of release of metals and sulfur to the environment. AMD communities contain fewer prokaryotic lineages than many other environments. However, it is notable that at least two archaeal and eight bacterial divisions have representatives able to thrive under the extreme conditions typical of AMD. AMD communities are characterized by a very limited number of distinct species, probably due to the small number of metabolically beneficial reactions available. The metabolisms that underpin these communities include organoheterotrophy and autotrophic iron and sulfur oxidation. Other metabolic activity is based on anaerobic sulfur oxidation and ferric iron reduction. Evidence for physiological synergy in iron, sulfur, and carbon flow in these communities is reviewed. The microbial and geochemical simplicity of these systems makes them ideal targets for quantitative, genomic-based analyses of microbial ecology and evolution and community function.

Growth of non-phototrophic microorganisms using solar energy through mineral photocatalysis

“…Our data demonstrate that the aerobic denitrifying (A. faecalis) and iron-oxidizing (A. ferrooxidans) bacteria can grow on energy released from photocatalysis of sulfides and oxides. In the modern environment, non-phototrophic microorganisms have been found in a number of extreme environments ranging from the driest desert 42 to the most acidic environments 43,44 . In these environments, organic matter is scarce and is generally produced by a subset of microorganisms such as chemolithotrophs 44 .…”

“…In these environments, organic matter is scarce and is generally produced by a subset of microorganisms such as chemolithotrophs 44 . The abundant existence of semiconducting minerals such as metal sulfides and oxides in the same environments [43][44] can produce photoelectrons through photocatalysis, which might have indirectly or directly fuelled non-phototrophic microorganisms, such as A. ferrooxidans and A. faecalis.…”

Metagenomics of extreme environments

“…As the major focus of JF Banfield"s group [45][46][47][48][49], acid mine drainage AMD) metagenomes revealed low-diversity microbial communities assembled into selfsufficient chemoautotrophic consortia [44,48]. From these data, the complete genomes of the bacterial AMD-specialists Leptospirillum group II and III, the archaeon Ferroplasma type II and the unculturable A-and G-Plasma archaeal clades were assembled [44].…”

The Catalytic Role of Acidithiobacillus ferrooxidans for Metals Extraction from Mining - Metallurgical Resource

“…Most acidophilic microorganisms can be isolated from these sources. [19][20][21][22] The most important role in the development of industrial bacterial leaching is played by the acidophilus bacteria Acidithiobacillus ferrooxidans. 12,23,24 In this paper we review the physiology of acidophilic microorganisms, and application areas of bioleaching with Acidithiobacillus ferrooxidans in copper mining and metallurgy, as well as the impacts of electrochemistry, type of minerals and addition of catalysts to recovery of metals on the catalytic activity of the bacteria .…”