The effect of O2and pressure on thiosulfate oxidation byThiomicrospira thermophila

Mining industry is a source of wealth but also of environmental pollution in Peru. In this study 12 colonies of actinomycetes were isolated in acidic cultures from mineral ores and concentrates from mines of the Peruvian highlands. The isolates were characterized phenotypically by microscopy and growth at different conditions as pH tolerance, temperature, and sodium chloride, heavy metals resistance; ferrous iron and thiosulfate oxidation. All isolates were identified as actinomycetes based on their cultural and spore characteristics. Most of the isolates were able to grow at 8 - 45°C and pH 4 - 11. 60% of isolates grew at 10% NaCl but none of them growth at 13%. Iron oxidation was shown by 60% of isolates at pH 4, but only 25% were able to oxidize iron at pH 2. Thiosulfate oxidation was not detected in any isolate. Most of the isolates showed capacity to grow in medium with 200 ppm of Pb, Fe, Zn and 100 ppm of Cu. All of the physiological characteristics found in this work indicate the potential of these isolates as source for bioremediation and bioleaching.

Download Full-text

RDE study of thiosulfate oxidation on gold

Journal of Electroanalytical Chemistry ◽

10.1016/j.jelechem.2014.10.018 ◽

2014 ◽

Vol 735 ◽

pp. 111-114 ◽

Cited By ~ 13

Author(s):

A.G. Zelinsky

Keyword(s):

Thiosulfate Oxidation

Download Full-text

Unraveling Fe(II)-oxidizing mechanisms in a facultative Fe(II) oxidizer Sideroxydans lithotrophicus ES-1 via culturing, transcriptomics, and RT-qPCR

10.1101/2021.08.18.456919 ◽

2021 ◽

Author(s):

Nanqing Zhou ◽

Jessica L. Keffer ◽

Shawn W. Polson ◽

Clara S Chan

Keyword(s):

Gene Expression ◽

Carbon Fixation ◽

Expression Profiles ◽

Gene Expression Profiles ◽

Sulfur Oxidation ◽

Complex Iii ◽

Initial Growth ◽

Gene Expression Response ◽

Oxidase Gene ◽

Thiosulfate Oxidation

Sideroxydans lithotrophicus ES-1 grows autotrophically either by Fe(II) oxidation or thiosulfate oxidation, in contrast to most other neutrophilic Fe(II)-oxidizing bacteria (FeOB) isolates. This provides a unique opportunity to explore the physiology of a facultative FeOB and constrain the genes specific to Fe(II) oxidation. We compared the growth of S. lithotrophicus ES-1 on Fe(II), thiosulfate, and both substrates together. While initial growth rates were similar, thiosulfate-grown cultures had higher yield with or without Fe(II) present, which may give ES-1 an advantage over obligate FeOB. To investigate the Fe(II) and S oxidation pathways, we conducted transcriptomics experiments, validated with RT-qPCR. We explored the long-term gene expression response at different growth phases (over days-week) and expression changes during a short-term switch from thiosulfate to Fe(II) (90 min). The dsr and sox sulfur oxidation genes were upregulated in thiosulfate cultures. The Fe(II) oxidase gene cyc2 was among the top expressed genes during both Fe(II) and thiosulfate oxidation, and addition of Fe(II) to thiosulfate-grown cells caused an increase in cyc2 expression. These results support the role of Cyc2 as the Fe(II) oxidase and suggest that ES-1 maintains readiness to oxidize Fe(II) even in the absence of Fe(II). We used gene expression profiles to further constrain the ES-1 Fe(II) oxidation pathway. Notably, among the most highly upregulated genes during Fe(II) oxidation were genes for alternative complex III, reverse electron transport and carbon fixation. This implies a direct connection between Fe(II) oxidation and carbon fixation, suggesting that CO2 is an important electron sink for Fe(II) oxidation.

Download Full-text