Dispersion of sulfur creates a valuable new growth medium formulation that enables earlier sulfur oxidation in relation to iron oxidation in Acidithiobacillus ferrooxidans cultures

2021 ◽  
Author(s):  
Yuta Inaba ◽  
Timothy Kernan ◽  
Alan C. West ◽  
Scott Banta
Keyword(s):  
Growth Medium ◽  
Acidithiobacillus Ferrooxidans ◽  
Iron Oxidation ◽  
Sulfur Oxidation ◽  
Medium Formulation

Regulation of the Iron and Sulfur Oxidation Pathways in the Acidophilic Acidithiobacillus Ferrooxidans

2009 ◽  
Vol 71-73 ◽  
pp. 163-166 ◽  
Author(s):  
A. Amouric ◽  
C. Appia-Ayme ◽  
A. Yarzabal ◽  
Violaine Bonnefoy
Keyword(s):  
Recombinant Proteins ◽  
Acidithiobacillus Ferrooxidans ◽  
Iron Oxidation ◽  
Sulfur Oxidation ◽  
Transcriptional Unit ◽  
Two Component ◽  
Number Of Genes ◽  
Genes Encoding ◽  
Transcriptional Units ◽  
Iron And Sulfur Oxidation

The acidophilic and strictly chemolithoautotrophic bacterium Acidithiobacillus ferrooxidans oxidizes ferrous (Fe(II)) to ferric (Fe(III)) iron and reduced inorganic sulfur compounds (RISC) to sulfuric acid, in oxic conditions. The redox proteins involved in the electron transfer between Fe(II) and oxygen are encoded in the same transcriptional unit, the rus operon. The expression of this operon is induced in the presence of Fe(II), but not Fe(III), and is not repressed in the presence of sulfur (S0). A number of genes differentially expressed in iron or sulfur conditions have been identified by microarrays transcript profiling. We show here that the presence of Fe(II) induced the expression of the genes involved in iron oxidation and repressed the expression of the genes involved in RISC oxidation. Identification of the regulator(s) involved in this transcriptional regulation is underway. Two genes encoding putative regulators belonging to two transcriptional units located downstream from the rus operon have been cloned. One regulator with a putative ironsulfur cluster belongs to the IscR family and the other belongs to the two component sensor/regulator family. Expression of both genes is induced in the presence of Fe(II) and is not repressed by S0. The recombinant proteins have been purified and gel shift assays with the target regulatory regions are in progress.

scholarly journals Dispersion of sulfur enables sulfur oxidation before iron oxidation in Acidithiobacillus ferrooxidans: A valuable formulation for the genetic engineering toolbox

2021 ◽  
Author(s):  
Yuta Inaba ◽  
Timothy Kernan ◽  
Alan West ◽  
Scott Banta
Keyword(s):  
Acidithiobacillus Ferrooxidans ◽  
Ferrous Iron ◽  
Iron Reduction ◽  
Fluorescent Protein ◽  
Energy Content ◽  
Iron Oxidation ◽  
Sulfur Oxidation ◽  
Surface Hydrophobicity ◽  
Substrate Utilization Pattern ◽  
Ferrous Iron Oxidation

Acidithiobacillus ferrooxidans are acidophilic chemolithoautotrophs that are commonly reported to exhibit diauxic population growth behavior where ferrous iron is oxidized before elemental sulfur when both are available, despite the higher energy content of sulfur. We have discovered sulfur dispersion formulations that enables sulfur oxidation before ferrous iron oxidation. The oxidation of dispersed sulfur can lower the culture pH within days below the range where aerobic ferrous iron oxidation can occur so that ferric iron reduction occurs which had previously been reported over extended incubation periods with untreated sulfur. Therefore, we demonstrate that this substrate utilization pattern is strongly dependent on the cell loading in relation to sulfur concentration, sulfur surface hydrophobicity, and the pH of the culture. Our dispersed sulfur formulation, lig-sulfur, can be used to support the rapid antibiotic selection of plasmid-transformed cells, which is not possible in liquid cultures where ferrous iron is the main source of energy for these acidophiles. Furthermore, we find that media containing lig-sulfur supports higher production of green fluorescent protein (GFP) compared to media containing ferrous iron. The use of dispersed sulfur is a valuable new tool for the development of engineered A. ferrooxidans strains and it provides a new method to control iron and sulfur oxidation behaviors.

How the RegBA Redox Responding System Controls Iron and Sulfur Oxidation in Acidithiobacillus ferrooxidans

2013 ◽  
Vol 825 ◽  
pp. 186-189 ◽  
Author(s):  
Danielle Moinier ◽  
Deborah Byrne ◽  
Agnès Amouric ◽  
Violaine Bonnefoy
Keyword(s):  
Acidithiobacillus Ferrooxidans ◽  
Ferrous Iron ◽  
Iron Oxidation ◽  
Regulatory Region ◽  
Sulfur Oxidation ◽  
Sulfur Compounds ◽  
Chemical Attack ◽  
Valuable Metals ◽  
Genes Encoding ◽  
Iron And Sulfur Oxidation

Valuable metals as well as ferrous iron and sulfur compounds are released from ore by ferric iron and sulfuric acid chemical attack. Biomining microorganisms allow the recycling of these products by oxidizing ferrous iron and/or sulfur compounds. The energy released from the oxidation of these substrates is used for the growth of the acidophilic chemolithoautotrophic bacterium Acidithiobacillus ferrooxidans. The respiratory pathways involved in these respiratory processes have been deciphered and the expression of the genes encoding these redox proteins is dependent on the electron donor present in the medium. Furthermore, in the presence of both ferrous iron and sulfur, the genes involved in iron oxidation are expressed before those involved in sulfur oxidation. We propose that the global redox responding two component system RegBA is responsible for this regulation since (i) the redox potential increases during iron oxidation but remains stable during sulfur oxidation and (ii) the transcriptional regulator RegA binds the regulatory region of a number of genes/operons involved in iron and sulfur oxidation. To understand the mechanism of the At. ferrooxidans RegBA system, the regA gene and the DNA corresponding to the DNA binding domain of RegA were cloned in an expression plasmid in Escherichia coli. The recombinant proteins, RegA and RegA-HTH respectively, were purified. The binding of RegA-HTH, phosphorylated and unphosphorylated RegA on the regulatory region of some target operons have been compared by gel shift mobility assay.

Biological iron oxidation-reduction and the effects on sulfur oxidation-reduction, denitrification and poly-P accumulation in an anaerobic-oxic activated sludge

2002 ◽  
Vol 46 (1-2) ◽  
pp. 55-60 ◽  
Author(s):  
R. Yamamoto-Ikemoto ◽  
T. Komori ◽  
S. Matsui
Keyword(s):  
Activated Sludge ◽  
Sulfate Reduction ◽  
Iron Reduction ◽  
Iron Oxidation ◽  
Sulfur Oxidation ◽  
Monod Equation ◽  
Oxidation Rates ◽  
Oxidation Reduction ◽  
Initial Iron ◽  
P Accumulation

Iron oxidation and reduction were examined using the activated sludge from a municipal plant. Iron contents of the activated sludge were 1–2%. Iron oxidation rates were correlated with the initial iron concentrations. Iron reducing rates could be described by the Monod equation. The effects of iron reducing bacteria on sulfate reduction, denitrification and poly-P accumulation were examined. Iron reduction suppressed sulfate reduction by competing with hydrogen produced from protein. Denitrification was outcompeted with iron reduction and sulfate reduction. These phenomena could be explained thermodynamically. Poly-P accumulation was also suppressed by denitrification. The activity of iron reduction was relatively high.

Are there multiple mechanisms of anaerobic sulfur oxidation with ferric iron in Acidithiobacillus ferrooxidans ?

2016 ◽  
Vol 167 (5) ◽  
pp. 357-366 ◽  
Author(s):  
Jiri Kucera ◽  
Eva Pakostova ◽  
Jan Lochman ◽  
Oldrich Janiczek ◽  
Martin Mandl
Keyword(s):  
Acidithiobacillus Ferrooxidans ◽  
Ferric Iron ◽  
Sulfur Oxidation ◽  
Anaerobic Sulfur Oxidation

scholarly journals A kinetic model of ferrous iron oxidation by Acidithiobacillus ferrooxidans in a batch culture

2005 ◽  
Vol 11 (2) ◽  
pp. 59-62 ◽  
Author(s):  
Dragisa Savic ◽  
Miodrag Lazic ◽  
Vlada Veljkovic ◽  
Miroslav Vrvic
Keyword(s):  
Kinetic Model ◽  
Acidithiobacillus Ferrooxidans ◽  
Ferrous Iron ◽  
Bubble Column ◽  
Iron Oxidation ◽  
Yield Coefficient ◽  
Transfer Rates ◽  
Ferrous Iron Oxidation ◽  
Menten Kinetic ◽  
Kinetics Of

The batch oxidation kinetics of ferrous iron by Acidithiobacillus ferrooxidans were examined at different oxygen transfer rates and pH in an aerated stirred tank and a bubble column. The microbial growth, oxygen consumption rate and ferrous and ferric iron were monitored during the biooxidation. A kinetic model was established on the basis of the Michaelis-Menten kinetic equation for bacterial growth and the constants estimated from experimental data (maximum specific growth rate 0.069 h-1, saturation constant 2.9 g/dm3, and biomass yield coefficient based on ferrous iron 0.003 gd.w./gFe). Values calculated from the model agreed well with the experimental ones regardless of the bioreactor type and pH conditions.

scholarly journals Kinetic Constant Variability in Bacterial Oxidation of Elemental Sulfur

2007 ◽  
Vol 73 (11) ◽  
pp. 3752-3754 ◽  
Author(s):  
Blanka Pokorna ◽  
Martin Mandl ◽  
Sarka Borilova ◽  
Pavla Ceskova ◽  
Romana Markova ◽  
...  
Keyword(s):  
Acidithiobacillus Ferrooxidans ◽  
Elemental Sulfur ◽  
Kinetic Constant ◽  
Sulfur Oxidation ◽  
Growth Yields ◽  
Resting Cells ◽  
Michaelis Constant ◽  
Bacterial Oxidation ◽  
Batch Cultures ◽  
Oxidation Rates

ABSTRACT Wide ranges of growth yields on sulfur (from 2.4 × 1010 to 8.1 × 1011 cells g−1) and maximum sulfur oxidation rates (from 0.068 to 1.30 mmol liter−1 h−1) of an Acidithiobacillus ferrooxidans strain (CCM 4253) were observed in 73 batch cultures. No significant correlation between the constants was observed. Changes of the Michaelis constant for sulfur (from 0.46 to 15.5 mM) in resting cells were also noted.

Phosphate removal and sulfate reduction in a denitrification reactor packed with iron and wood as electron donors

2008 ◽  
Vol 58 (7) ◽  
pp. 1405-1413 ◽  
Author(s):  
Takahiro Yamashita ◽  
Ryoko Yamamoto-Ikemoto
Keyword(s):  
Sulfate Reduction ◽  
Phosphorus Removal ◽  
Iron Oxidation ◽  
Sulfur Oxidation ◽  
Phosphate Removal ◽  
Electron Donors ◽  
Rrna Gene ◽  
Phylogenetic Groups ◽  
Primer Sets ◽  
Heterotrophic Denitrification

Phosphorus removal and denitrification using iron and wood as electron donors were examined in a laboratory-scale biological filter reactor. Phosphorus removal and denitrification using iron and wood continued for 1,200 days of operation. Wood degradation by heterotrophic denitrification and iron oxidation by hydrogenotrophic denitrification occurred simultaneously. In the biofilm inside the wood, not only heterotrophic denitrification activity but also sulfate reduction and sulfur denitrification activities were recognized inside the wood, indicating that a sulfur oxidation-reduction cycle was established. Sulfate reduction and denitrification were accelerated with the addition of cellulose. Microbial communities of sulfate-reducing bacteria by PCR primer sets could be amplified in the biofilm in the reactors. The dissimilatory sulfite reductase gene and the 16S rRNA gene of six phylogenetic groups of SRB in the reactors were analyzed. Some SRB group-specific primers-amplification products were obtained inside the wood and around iron.

Iron and sulfur oxidation pathways of Acidithiobacillus ferrooxidans

2019 ◽  
Vol 35 (4) ◽  
Author(s):  
Yue Zhan ◽  
Mengran Yang ◽  
Shuang Zhang ◽  
Dan Zhao ◽  
Jiangong Duan ◽  
...  
Keyword(s):  
Acidithiobacillus Ferrooxidans ◽  
Sulfur Oxidation ◽  
Iron And Sulfur Oxidation
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