Diversity of the communities of acidophilic chemolithotrophic microorganisms in natural and technogenic ecosystems

Abstract

The communities of acidophilic chem olithotrophic microorganisms (ACM) are formed in sulfide ore deposits, mine waters, pyrite coals, the wastes of ore mining and processing industry in differ ent geographical and climatic zones, as well as in the pulps of reactors for the technologies of bacterialchemical oxidation of sulfide ore concentrates, i.e., in the presence of sulfide minerals and their oxidation products, elemental sulfur, reduced sulfur com pounds, and ferrous iron. As a result of their activity, the medium is acidified, sometimes to pH 0.5 or less, and the concentrations of heavy metals and toxic ele ments (copper, zinc, nickel, cobalt, arsenic, etc.) increase. These microorganisms therefore belong to extreme chemolithotrophic acidophiles. They include representatives of bacteria (both gram negative and gram positive) and archaea.Tables 1-3 present the best studied and most fre quently occurring ACM, the substrates they oxidize, and the ranges and optimal values of pH and tempera ture for their growth . It can be seen that some microorganisms can oxidize all inorganic substrates mentioned above, e.g., gram negative bacteria of the genus Acidithiobacillus (At. ferrooxidans, At. fer rivorans), gram positive bacteria of the genus Sulfoba cillus (S. thermosulfidooxidans, S. thermotolerans, S. benefaciens), and the archaeon Acidianus (Ac.) bri erleyi. Ferrous iron, elemental sulfur and sulfide min erals are used as energy sources by Metallosphaera sedula and M. prunae. Other microorganisms can obtain energy by oxidizing only ferrous iron or pyrite: Leptospirillum ferrooxidans, L. ferriphilum, and Ferro plasma acidiphilum. Most of the microorganisms (At. thiooxidans, At. caldus, and archaea) use elemen tal sulfur and reduced sulfur compounds as an energy substrate. The pH optima for the growth of these microorganisms are different, but all of them are in the range of acidic values. ACM live in a broad tempera ture range of 4 to 90°С. They include mesophiles with the optimal temperature for growth and oxidation of the energy substrate in the range of 28-35°С, moder ate thermophiles with the temperature optimum at 40 to 55°С, and thermophiles with the temperature opti mum above 60°С. The latter include mainly archaea. For instance, Ac. infernus has a temperature optimum for growth at 90°С [20].Abstract-The main representatives of acidophilic chemolithotrophs oxidizing sulfide minerals, ferrous iron, elemental sulfur, and reduced sulfur compounds and forming microbial communities in the natural and technogenic ecosystems with low pH values and high concentrations of heavy metal ions are listed. The spe cies and strain diversity of the communities and environmental factors affecting their composition (temper ature, pH value, energy substrate, mineralogical composition of sulfide ore concentrates, the presence of organic substances, and level of aeration) are analyzed. Involvement of mobile genetic elements (IS elements and plasmids) in the structural changes of the chromosomal DNA in the course of switching m...

Environmental factors influencing the structural dynamics of soil microbial communities during assisted phytostabilization of acid-generating mine tailings: A mesocosm experiment

“…iron oxidizers) and Crenarchaeota ( e.g . sulfur oxidizers) are actually favored in acidic soils (Erguder et al, 2009; Kondrat‧eva et al, 2012; Lehtovirta et al, 2009; Nicol et al, 2008). Thus, the increase in archaeal band number in the planted treatments as the pH declined (Table 1) may correspond to increases in some of these acidophilic archaeal populations (Kondrat’eva et al, 2012).…”

Composition of aboriginal consortium of microorganisms from coal mines dumps

“…The leaders in leaching of metals were the acidophilic chemolithotrophic bacteria (ACB), including the genera Acidithiobacillus, Sulfobacillus, Leptospirillum, Acidimicrobium, Acidianus, Ferroplasma [12,14,20,24,28,38], and for that reason this groups of bacteria were studied. The taxonomy of bacteria of Acidithiobacillus is based on their relationship to energy supply, mineral background of the culture medium with adding fer rous iron compounds in the form FeSO 4 ×7H 2 O (44.5 g/dm 3 ), elementary sulfur (5.0 g/dm 3 ) and sodium thiosulfate Na 2 S 2 O 3 (5.0 g/dm 3 ) [20,28].…”

“…Evaluation of the biogeochemical activity has showed that under natu ral conditions these microorganisms played important role in leaching of metals from sulphide ores. Similar processes have occurred in the technogenic wastes which de rived from the corresponding natural substrates [16,24,29,41]. The processing of pri mary mineral raw materials in the hostile environment and further accumulation and preservation of generated waste and heaps with changing of temperature, acidity, con tent of high concentrations of heavy metals have made conditions for a wide variety of their own microbiota [16,17,34].…”

Selection of a community of acidochemolithotrophic microorganisms with a high oxidation rate of pyrrhotite-containing sulphide ore flotation concentrate

“…These are the mineralogical and elemental composition of the sub strate to be oxidized, temperature, pH value, and the presence of organic substances [3].…”