Physiological and Morphological Characteristics of Acidophilic Bacteria Leptospirillum ferriphilum and Acidithiobacillus thiooxidans, Members of a Chemolithotrophic Microbial Consortium

• Published in: Microbiology (New York) Vol. 87; no. 3; pp. 326 - 338
• Main Authors: Panyushkina, A. E., Tsaplina, I. A., Kondrat’eva, T. F., Belyi, A. V., Bulaev, A. G.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 2018; Springer Nature B.V
• Subjects: Acidophilic bacteria; Biomedical and Life Sciences; Cell size; Experimental Articles; Filaments; Iron; Life Sciences; Medical Microbiology; Microbiology; Oxidation; pH effects; Physical characteristics; Pyrite; Rods; Sulfur oxidation; pyrrhotite pyrite–arsenopyrite concentrate; consortium of thermoacidophilic chemolithotrophic microorganisms; oxidative activity of; morphoforms of; and
• ISSN: 0026-2617; 1608-3237
• DOI: 10.1134/S0026261718030086

A thermoacidophilic consortium of chemolithotrophic microorganisms oxidizing the concentrate of high-pyrrhotite pyrite−arsenopyrite ore at 38–40°C was isolated. The most active members of the consortium were identified as
Leptospirillum ferriphilum
,
Acidithiobacillus thiooxidans
,
Ferroplasma acidiphilum
, and
Sulfobacillus thermotolerans
.
Leptospirillum
and
Thiobacillus
species were the most numerous members of the consortium and had the highest activity of ferrous iron and sulfur oxidation, respectively. The optimal temperature values for the growth of both isolates were within 35–38°C. The optimal ranges of initial pH were 1.0–1.2 and 1.75–1.85 for leptospirilla and 1.7–3.3 for thiobacilli with the pH optimum of 1.9. Significant polymorphism and specific cyclic growth with formation of vibrios, spirilla, rods with different end shape, spiral filaments, numerous “pseudococci,” and densely packed spiral filaments surrounded by a sheath were revealed for the
Leptospirillum
isolate. Two latter morphoforms of
L. ferriphilum
were not previously described. Differences in ability of the morphoforms to oxidize Fe
2+
were revealed. For the first time, the possibility of growth in the presence of organic substances was demonstrated for
A. thiooxidans
. The rates of growth and substrate oxidation, cell size, and the maximal cell yield decreased insignificantly in comparison with the lithoautotrophic strain.