Thiobacillus bacteria

As stated above, the presence of proteins on the surface of sulfur globules stored intracellularly has been demonstrated [8, 37]. These well-defined proteins act as a membrane between the cytoplasm and the intracellular sulfur particle. It is not known whether the proteins associated with the sulfur particles excreted by Thiobacillus bacteria are well-defined proteins synthesized by the bacterium or if they are originating from organic compounds already present in the liquid reactor system. 

The corrosion of concrete sewer pipe is not a direct result of the presence of hydrogen sulfide gas in the headspace above the water rather the primary mechanism of corrosion is caused by the presence of Thiobacillus bacteria, which reside on the invert of the pipe see Figure 10.7. This genus of bacteria has the ability to oxidize hydrogen sulfide gas to form sulfate, which results in the formation of sulfuric acid see reaction (10.11) ... 

They are also found on stone buildings and statues and probably account for much of the accelerated damage commonly attributed to acid rain. Where Thiobacillus bacteria are associated with corrosion, they are almost always accompanied by SRB. Thus, both types of organisms are able to draw energy from a S5mergistic sulfur cycle. 

Acid producers. Many bacteria produce acids. Acids may be organic or inorganic depending on the specific bacterium. In either case, the acids produced lower the pH, usually accelerating attack. Although many kinds of bacteria may generate acids, Thiobacillus thiooxidans and Clostridium species have most often been linked to accelerated corrosion on steel. 

Thiobacillus thiooxidans is an aerobic organism that oxidizes various sulfur-containing compounds to form sulfuric acid. These bacteria are sometimes found near the tops of tubercles (see Chap. 3, Tubercu-lation ). There is a symbiotic relationship between Thiobacillus and sulfate reducers Thiobacillus oxidizes sulfide to sulfate, whereas the sulfate reducers convert sulfide to sulfate. It is unclear to what extent Thiobacillus directly influences corrosion processes inside tubercles. It is more likely that they indirectly increase corrosion by accelerating sulfate-reducer activity deep in the tubercles. 

Gram negative Bacteria cells which lose the crystal violet during the decolorizing step and are then colored by the counterstain. Pseudomonas and Thiobacillus are examples of gram negative strains. 

The resulting environment is low in pH and extremely corrosive. Thiobacillus and Beggiatoa are good examples of this form of bacteria. 

Strains of some facultatively heterotrophic and methylotrophic bacteria can use CS2 as sole energy source, and under aerobic conditions also COS, dimethyl sulfide, dimethyl disulfide, and thioacetate (Jordan et al. 1995). It was proposed that the strains belonged to the genus Thiobacillus, though they are clearly distinct from previously described species, and they have now been assigned to Paracoccus denitrificans (Jordan et al. 1997). 

In the leaching process, bacteria such as Thiobacillus ferroxidans and those belonging to the Sulfolobus genera, play a major role in the oxidation reactions at moderate and higher temperatures respectively. The oxidation of sulfides by bacteria is typified by the reactions of pyrite, a common accessory mineral in primary copper ore bodies this reaction can be considered to proceed through two stages ... 

Some metals can be converted to a less toxic form through enzyme detoxification. The most well-described example of this mechanism is the mercury resistance system, which occurs in S. aureus,43 Bacillus sp.,44 E. coli,45 Streptomyces lividans,46 and Thiobacillus ferrooxidans 47 The mer operon in these bacteria includes two different metal resistance mechanisms.48 MerA employs an enzyme detoxification approach as it encodes a mercury reductase, which converts the divalent mercury cation into elemental mercury 49 Elemental mercury is more stable and less toxic than the divalent cation. Other genes in the operon encode membrane proteins that are involved in the active transport of elemental mercury out of the cell.50 52... 

Sublette [285] describes a process for desulfurizing sour natural gas using another commonly known chemolithotrophic microorganism, the aerobic bacterium T. denitrifi-cans. This patent describes a process wherein bacteria of the Thiobacillus genus convert sulfides to sulfates under aerobic conditions. Sublette defined the ideal characteristics of a suitable microorganism for the oxidative H2S removal from gaseous streams as ... 

Chandra, D. Roy, P. Mishra, A.K., et al., Removal of Sulphur From Coal by Thiobacillus Ferroxidans and by Mixed Acidophilic Bacteria Present in Coal. Fuel, 1979. 59(4) pp. 249-252. 

The pK of Ca2+aq (204), 12.6 at zero ionic strength, rising to over 13 as ionic strength increases, means that concentrations of CaOH+aq will be negligible in body fluids (lpolluted waters, and under all conditions of biological relevance, from the very low pHs of 0.5 (Thiobacillus thiooxidans) to 1.5 at which bacteria used for oxidative metal extraction operate (205), through acid soils and acid rain (pH 3 to 6), streams, rivers, and oceans (pH 6 to 8), soda lakes (pH 10), up to the pHs of 11 or more in Jamaican Red Mud slurry ponds (206) (cf. Section II.C.l below). 

Finally, whereas most laboratory experiments have been conducted in largely abiotic environments, the action of bacteria may control reaction rates in nature (e.g., Chapelle, 2001). In the production of acid drainage (see Chapter 31), for example, bacteria such as Thiobacillus ferrooxidans control the rate at which pyrite (FeS2) oxidizes (Taylor et al., 1984 Okereke and Stevens 1991). Laboratory ob-... 

The aerobic bacteria responsible for this oxidation of hydrogen sulfide to sulfuric acid belong to the aerobic and autotrophic Thiobacillus family (Sand, 1987 Milde et al., 1983). These bacteria may be active at rather low pH values. Thiobacillus concretivorus is active at pH values between about 0.5 and 5 and may produce solutions of sulfuric acid up to about 7%. To be active, it requires that other species of the Thiobacillus family bring down the pH value. 

Two amicyanins have been a recent focus of attention [84, 85], These are from the methylotrophic bacteria Pseudomonas AMI and Thiobacillus versutus,... 

Peck then became interested in sulfate-reducing bacteria, which he had got to know in Gest s laboratory. To study the reduction of sulfate. Peck worked in Fritz Lipmann s laboratory in Massachussetts General Hospital (1956) and with Lipmann at Rockefeller University (1957). Lipmann started work on active sulfate in 1954 with Helmut Hilz as a postdoctoral fellow and studied the activation of sulfate to APS and PAPS. Lipmann had left the active sulfate projects by 1957 and started, at Rockefeller University, the studies on protein synthesis. Peck published one paper on the reduction of sulfate with hydrogen in extracts of Desulfovibrio desul-furicans (1959) and one on APS as an intermediate on the oxidation of thiosulfate by Thiobacillus thioparus (1960). 

Peck s hrst signihcant contribution was to look at Thiobacillus thioparus (the type species of the genus Thiobacillus) through the eyes of one who knew a lot about sulfate-reducing bacteria and about the enzymes involved in sulfate metabolism in yeast and mammalian tissues. This led him to think maybe the same enzymes are involved in sulfur oxidation as in reduction. The seminal paper of 1960 showed that this was indeed the case. 

Hiraishi A, Nagashima KVR Katayama Y. 1998. Phylogeny and photosynthetic featnres of Thiobacillus acidophilus and related acidophilic bacteria its transfer to the genns Acidiphilium as Acidiphilium acidophilum comb. nov. Int J Syst Bacteriol 48 1389-98. 

Lyalikova NN, Khizhnyak TV. 1996. Reduction of heptavalent technetium by acidophilic bacteria of the genus Thiobacillus. Microbiology 65 468-73. 

Sulfor oxidizing bacteria oxidize sulfide and sulfite to sulfate. The decrease of oxygen [94,95] as well as the alteration of pH [96] can be used as indicators of these reactions. With a Thiobacillus thioparus-containing sensor, a detected limit of 4 pmol/1 sulfite is reached [94]. The detection limit of a sensor with Thiobacillus thiooxydans for sulfide is 0.02 mmol/1 only [95]. 

The ability of the chemolithoautotrophic bacteria Thiobacillus ferrooxidans to oxidize Fe has already been utilized for construction of a microbial sensor for the determination of iron [101]. The limit of determination of this biosensor is 60 pmol 1" with a response time ranging from 30 s to 5 min, depending on the Fe +-concentration in the sample. 

Organisms such as Thiobacillus thiooxidans and Clostridium species have been linked to accelerated corrosion of mild steel. Aerobic Thiobacillus oxidizes various sulfur-containing compounds such as sulfides to sulfates. This process promotes a symbiotic relationship between Thiobacillus and sulfate-reducing bacteria. Also, Thiobacillus produces sulfuric acid as a metabolic by-product of sulfide oxidation. 

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