Evidence of weak interaction between ferric iron and extracellular polymeric substances of Acidithiobacillus ferrooxidans

The presence of extracellular polymeric substances (EPS) is important in the building of biofilms on mineral surfaces, increasing the bioleaching activity, as well as protecting the cells from adverse environmental conditions. The objective of this work was to study the effect of galactose in EPS production by Acidithiobacillus ferrooxidans. The experiences were performed in shake flask of 250 mL at 30 °C, 200 rpm and at an initial pH of 1.8. In order to establish the natural tolerance of the strain, its growth behaviour was evaluated at high ferric iron concentrations by adding consecutively the equivalent of 9 g/L of ferrous iron each time it was depleted in the broth. Cell growth stopped once ferric iron concentration increased up to 38 g/L. In order to determine the optimal conditions for EPS production, experiments were run in a chemostat of 0.5 L, operated at a constant dilution rate of 0.03 h-1. Different steady states were obtained varying feeding concentrations of galactose (0.15%; 0.25% and 0.35%) and carbon dioxide (180 ppm and 360 ppm). , Cells grown in the chemostat at optimum operation conditions were used as inoculum to determine oxidative capacity of the microorganisms overproducing EPS. The EPS was quantified using confocal laser scanning microscopy (CLSM), labelling the cells with propidium iodide and EPS carbohydrates with wheat germ agglutinin (WGA). The higher volume production of EPS was observed in cells grown using 360 ppm of CO2 and 0.35% of galactose. Also it was observed a size increment of cells, compared to cells grown in culture medium having 9 g/L of ferrous iron where presence of EPS was no detected. The results revealed that EPS overproducing A. ferrooxidans showed a tolerance to ferric iron concentration almost 9.5 g/L higher than the natural tolerance of cells grown in absence of galactose. Presence of galactose in culture medium stimulated the EPS production.

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Surface Characteristic of Pyrrhotite Bio-Oxidized by Acidithiobacillus Ferrooxidans

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.343-344.920 ◽

2011 ◽

Vol 343-344 ◽

pp. 920-925

Author(s):

Jiang Lei

Keyword(s):

Acidithiobacillus Ferrooxidans ◽

Extracellular Polymeric Substances ◽

Surface Characteristic

This paper deals with the surface characteristic of pyrrhotite bio-oxidized byAcidithiobacillus ferrooxidans. Large amounts of jarosite and element sulfur were determined in the bio-oxidation processe of pyrrhotite. More complicatedly, biofilm exists on the surface of pyrrhotite. This type of structured community ofA. ferrooxidanswas enclosed in the extracellular polymeric substances (EPS), and covered with the deposition generated in the bio-oxidation processe of pyrrhotite.

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

Research in Microbiology ◽

10.1016/j.resmic.2016.02.004 ◽

2016 ◽

Vol 167 (5) ◽

pp. 357-366 ◽

Cited By ~ 15

Author(s):

Jiri Kucera ◽

Eva Pakostova ◽

Jan Lochman ◽

Oldrich Janiczek ◽

Martin Mandl

Keyword(s):

Acidithiobacillus Ferrooxidans ◽

Ferric Iron ◽

Sulfur Oxidation ◽

Anaerobic Sulfur Oxidation

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Mechanism of bioleaching chalcopyrite by Acidithiobacillus ferrooxidans in agar-simulated extracellular polymeric substances media

Journal of Central South University of Technology ◽

10.1007/s11771-010-0011-9 ◽

2010 ◽

Vol 17 (1) ◽

pp. 56-61 ◽

Cited By ~ 11

Author(s):

Run-lan Yu ◽

Jian-xi Tan ◽

Gou-hua Gu ◽

Yue-hua Hu ◽

Guan-zhou Qiu

Keyword(s):

Acidithiobacillus Ferrooxidans ◽

Extracellular Polymeric Substances

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Interaction mechanism of Cu2+, Fe3+ ions and extracellular polymeric substances during bioleaching chalcopyrite by Acidithiobacillus ferrooxidans ATCC2370

Transactions of Nonferrous Metals Society of China ◽

10.1016/s1003-6326(13)62450-4 ◽

2013 ◽

Vol 23 (1) ◽

pp. 231-236 ◽

Cited By ~ 17

Author(s):

Run-lan YU ◽

Jing LIU ◽

An CHEN ◽

Dai-li ZHONG ◽

Qian LI ◽

...

Keyword(s):

Acidithiobacillus Ferrooxidans ◽

Extracellular Polymeric Substances ◽

Interaction Mechanism

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EPS Production during Adaptation of Acidithiobacillus ferrooxidans to High Ferric Ion Concentration

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.825.115 ◽

2013 ◽

Vol 825 ◽

pp. 115-119 ◽

Cited By ~ 2

Author(s):

Albert Saavedra ◽

Beatriz Pavez ◽

Mauricio Diaz ◽

Juan Carlos Gentina

Keyword(s):

Acidithiobacillus Ferrooxidans ◽

Ferrous Iron ◽

Ferric Iron ◽

Iron Concentration ◽

Laser Scanning Microscopy ◽

Ion Concentration ◽

Ferric Ion ◽

Growth Behaviour ◽

Ion Concentrations ◽

Iron Concentrations

The ability ofAcidithiobacillus ferrooxidansto get its energy from the oxidation of ferrous iron and the inhibitory effect of high ferric iron concentrations on its growth behaviour has been extensively studied. Furthermore it is known thatA. ferrooxidansexudes organic substances called extracellular polymeric substances (EPS), which could play a role in its protection against adverse environmental conditions. In this context, the aim of this work was to study the production of EPS during adaptation ofA. ferrooxidansto high ferric ion concentrations. The experiments were performed in shake flasks of 250 mL at 30 °C, 200 rpm and at an initial pH of 1.8. In order to establish the natural tolerance of the strain, its growth behaviour was evaluated at high ferric iron concentrations by adding consecutively the equivalent of 9 g/L of ferrous iron each time it was depleted in the broth. Cell growth stopped once ferric iron concentration increased up to 38 g/L. The adaptation consisted in eight sub-cultures run in parallel at initial concentrations of ferrous iron of 18, 27 and 36 g/L. The EPS was quantified as micro volumes using confocal laser scanning microscopy (CLSM), labelling the cells with propidium iodide and EPS carbohydrates with wheat germ agglutinin (WGA). During the adaptation procedure it was observed an increase in the ferric ion volumetric productivity of subcultures run with 27 and 36 g/L, as a result of cell adaptation. The amount of EPS exuded by cells was higher along with those experimental conditions having higher ferric iron concentrations. It was not detected EPS on cells grown on 9 g/L of ferrous iron. This study found that the adapted strain showed higher production of EPS at high ferric ion concentrations and higher ferric ion tolerance than non-adapted ones.

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The ferric iron uptake regulator (Fur) from the extreme acidophile Acidithiobacillus ferrooxidans

Microbiology ◽

10.1099/mic.0.27581-0 ◽

2005 ◽

Vol 151 (6) ◽

pp. 2005-2015 ◽

Cited By ~ 27

Author(s):

R. Quatrini ◽

C. Lefimil ◽

D. S. Holmes ◽

E. Jedlicki

Keyword(s):

Gene Expression ◽

Stress Responses ◽

Acidithiobacillus Ferrooxidans ◽

Iron Uptake ◽

Ferric Iron ◽

Sequence Similarity ◽

Cross Reactivity ◽

Mobility Shift ◽

E Coli ◽

Protein Levels

Acidithiobacillus ferrooxidans is a Gram-negative bacterium that lives at pH 2 in high concentrations of soluble ferrous and ferric iron, making it an interesting model for understanding the biological mechanisms of bacterial iron uptake and homeostasis in extremely acid conditions. A candidate fur AF (Ferric Uptake Regulator) gene was identified in the A. ferrooxidans ATCC 23270 genome. FurAF has significant sequence similarity, including conservation of functional motifs, to known Fur orthologues and exhibits cross-reactivity to Escherichia coli Fur antiserum. The fur AF gene is able to complement fur deficiency in E. coli in an iron-responsive manner. FurAF is also able to bind specifically to E. coli Fur regulatory regions (Fur boxes) and to a candidate Fur box from A. ferrooxidans, as judged by electrophoretic mobility shift assays. FurAF represses gene expression from E. coli Fur-responsive promoters fiu and fhuF when expressed at high protein levels. However, it increases gene expression from these promoters at low concentrations and possibly from other Fur-regulated promoters involved in iron-responsive oxidative stress responses.

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Ferric iron uptake genes are differentially expressed in the presence of copper sulfides in Acidithiobacillus ferrooxidans strain LR

Antonie van Leeuwenhoek ◽

10.1007/s10482-010-9533-2 ◽

2010 ◽

Vol 99 (3) ◽

pp. 609-617 ◽

Cited By ~ 6

Author(s):

Lúcio F. C. Ferraz ◽

Leandro C. L. Verde ◽

Renato Vicentini ◽

Ana P. Felício ◽

Marcelo L. Ribeiro ◽

...

Keyword(s):

Acidithiobacillus Ferrooxidans ◽

Iron Uptake ◽

Ferric Iron ◽

Differentially Expressed ◽

Copper Sulfides

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Comparison of the Biological and Chemical Synthesis of Schwertmannite at a Consistent Fe2+ Oxidation Efficiency and the Effect of Extracellular Polymeric Substances of Acidithiobacillus ferrooxidans on Biomineralization

Materials ◽

10.3390/ma11091739 ◽

2018 ◽

Vol 11 (9) ◽

pp. 1739 ◽

Cited By ~ 6

Author(s):

Yongwei Song ◽

Yelin Liu ◽

Heru Wang

Keyword(s):

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Acidithiobacillus Ferrooxidans ◽

Extracellular Polymeric Substances ◽

Shell Shape ◽

X Ray ◽

Removal Capacity ◽

The Difference ◽

Oxidation Efficiency

Schwertmannite is an environmental mineral material that can promote the natural passivation of heavy metal elements, thereby reducing environmental pollution from toxic elements. However, the fundamental reason for the difference between the chemically (H2O2-FeSO4) and biologically (Acidithiobacillus ferrooxidans-FeSO4) synthesized schwertmannite is still unclear. In this study, X-ray diffraction, scanning electron microscopy, the Brunauer–Emmett–Teller method, and X-ray fluorescence spectrometry were used to compare the structure, specific surface area, and elemental composition of schwertmannite synthesized by biological and chemical methods. The removal capacity of As(III) by the two kinds of schwertmannite and the effects of extracellular polymeric substances (EPS) on biogenetic schwertmannite were also investigated. At a consistent Fe2+ oxidation efficiency, the chemical method synthesized more schwertmannite than the biological method over a 60-h period. The biosynthesized schwertmannite had a “chestnut shell” shape, with a larger particle size and specific surface than the chemically synthesized schwertmannite, which was relatively smooth. The saturated adsorption capacities of the biologically and chemically synthesized schwertmannite were 117.0 and 87.0 mg·g−1, respectively. After exfoliation of the EPS from A. ferrooxidans, the biosynthesized schwertmannite displayed a “wool ball” shape, with rough particle surfaces, many microporous structures, and a larger specific surface area. The schwertmannite yield also increased by about 45% compared with that before exfoliation, suggesting that the secretion of EPS by A. ferrooxidans can inhibit the formation of schwertmannite.

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