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.

Control of filamentous bulking and interactions among sulfur oxidation-reduction and iron oxidation-reduction in activated sludge using an iron coagulant

1998 ◽  
Vol 38 (8-9) ◽  
pp. 9-17 ◽  
Author(s):  
Ryoko Yamamoto-Ikemoto ◽  
Saburo Matsui ◽  
Tomoaki Komori ◽  
Edja Kofi Bosque-Hamilton
Keyword(s):  
Activated Sludge ◽  
Sulfate Reduction ◽  
Iron Oxidation ◽  
Sulfur Oxidation ◽  
Phosphate Removal ◽  
Aeration Tank ◽  
Filamentous Bulking ◽  
Sulfate Reducing ◽  
Oxidation Reduction ◽  
Reducing Bacteria

The effect of iron coagulant on control of filamentous bulking and phosphate removal was investigated using a laboratory scale activated sludge process. Sulfate reduction was correlated to activated sludge bulking. When FeCl2 was added to the aeration tank, most of the phosphate was removed. Sulfate reduction and filamentous bulking were also suppressed. The addition of FeCl2 was also effective in suppressing phosphate release and sulfide production from wasted sludge. Interactions among sulfur oxidation-reduction and iron oxidation-reduction were examined in the batch experiments. When FeCl2 was added, iron reducing bacteria outcompeted sulfate reducing bacteria and iron oxidizing bacteria grew predominantly.

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.

Symbiosis and competition among sulfate reduction, filamentous sulfur, denitrification, and poly-p accumulation bacteria in the anaerobic-oxic activated sludge of a municipal plant

1996 ◽  
Vol 34 (5-6) ◽  
pp. 119-128 ◽  
Author(s):  
Ryoko Yamamoto-Ikemoto ◽  
Saburo Matsui ◽  
Tomoaki Komori ◽  
E. J. Bosque-Hamilton
Keyword(s):  
Organic Acids ◽  
Activated Sludge ◽  
Sulfate Reduction ◽  
Sulfide Oxidation ◽  
Sulfate Reducing Bacteria ◽  
Sulfur Cycle ◽  
Sulfate Reducing ◽  
P Accumulation ◽  
Relationship Of ◽  
Reducing Bacteria

Symbiosis and competition were examined among sulfate reducing bacteria (SRB), filamentous sulfur bacteria (FSB), denitrification bacteria (DNB) and poly-P accumulation bacteria (PAB) in the activated sludge of a municipal plant operated under anaerobic-oxic conditions. Batch experiments were carried out using settled sewage from the same plant as the substrate under several conditions. Under oxic conditions, both sulfate reduction and sulfide oxidation occurred simultaneously, making a symbiotic relationship of SRB and FSB for establishment of a sulfur cycle sustaining the energy requirements. Under anoxic conditions, denitrification was dominant because DNB outcompeted PAB and SRB for organic acids. Under anaerobic conditions, phosphate release and sulfate reduction occurred simultaneously. SRB produced for moles of acetate from four moles of propionate and/or unknown substances by reduction of three moles of sulfate. PAB competed with sulfate-reducing bacteria for organic acids such as propionate. However, PAB utilized acetate produced by SRB.

Effect of fluctuating oxygen concentration on iron oxidation at the pelagic ferrocline of a meromictic lake

2015 ◽  
Vol 12 (6) ◽  
pp. 723 ◽  
Author(s):  
Jenny Bravidor ◽  
Julika Kreling ◽  
Andreas Lorke ◽  
Matthias Koschorreck
Keyword(s):  
Oxygen Concentration ◽  
Iron Reduction ◽  
Iron Oxidation ◽  
Meromictic Lake ◽  
Chemical Gradients ◽  
Oxidation Rates ◽  
Ph Dependency ◽  
Biogeochemical Transformations ◽  
Iron Profile ◽  
Physical And Chemical

Environmental context The cycling of iron plays an important role in pelagic boundary zones such as the oxic–anoxic interface where physical and chemical gradients occur. The turnover of iron in this zone depends on oxygen fluctuation and the duration of the fluctuation event. This study increases the understanding of biogeochemical iron transformation in such hotspots. Abstract In stratified iron-rich lakes, the interface between oxic and anoxic water bodies, the oxycline, is accompanied by a steep gradient of dissolved iron, the ferrocline. It is a hotspot of biogeochemical transformations, namely the cycling of iron (Fe). The rate of iron oxidation, both chemical and microbial, depends on pH, iron and oxygen concentration, and microbial activity. We investigated the ferrocline of the meromictic Lake Waldsee to find out how the ferrocline is influenced by fluctuating oxygen concentrations. We measured diurnal fluctuations of Fe2+, O2 and pH along vertical profiles during two campaigns in July and September 2011 as well as rates of iron oxidation in laboratory incubations. The oxygen content of the water column varied both between the campaigns and diurnally. We observed a diurnal intrusion of O2 into the ferrocline. The diurnal signal was visible in the iron profile in July but not in September. Iron oxidation rates determined in the laboratory demonstrate the importance of microbial iron reduction and the strong pH dependency. We related the reaction timescales for iron oxidation to the characteristic timescale of oxygen fluctuations by calculating non-dimensional numbers. This analysis showed that an oxygenation event had to last at least 10h in order to affect the depth and vertical extent of the ferrocline, which was the case in July but not in September. Our results show that the duration of events can be an important parameter regulating biogeochemical interactions in pelagic redoxclines.

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.

scholarly journals Kinetics of iron oxidation-reduction in hydrous silicic melts

2002 ◽  
Vol 87 (7) ◽  
pp. 829-837 ◽  
Author(s):  
Fabrice Gaillard ◽  
Bruno Scaillet ◽  
Michel Pichavant
Keyword(s):  
Iron Oxidation ◽  
Oxidation Reduction ◽  
Kinetics Of
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