Thiobacillus metabolism

YouattJB. 1954. Studies on the metabolism of thiobacillus thiocyanoxidans. J Gen Microbiol 11 139-149. 

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. 

Lyric RM, Suzuki I. 1970. Enzymes involved in the metabolism of thiosulfate by Thiobacillus thioparus. II. Properties of adenosine 5 -phosphosulfate reductase. Can J Biochem 48 344-54. 

Santer M, Margulies M, Klinman N, Kaback R. 1960. Role of inorganic phosphate in thiosulfate metabolism by Thiobacillus thioparus. J Bacteriol 79 313-20. 

Vishniac W. 1952. The metabolism of Thiobacillus thioparus. I. The oxidation of thiosulfate. J Bacteriol 64 363-73. 

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. 

Oxidation of insoluble mineral sulfides to the usually water-soluble sulfates (PbS04 is an exception) can also be carried out in many cases by microbial leaching, that is, by the use of bacteria such as Thiobacillus fer-rooxidans which can use the sulfide-sulfate redox cycle to drive metabolic processes. The overall reaction still consumes oxygen... 

Mazzotta, M.Y. Johnson, E.J. Adenylate kinase from Thiobacillus neapoli-tanus. Unique properties, possibly designed to serve a unique metabolic function. Biochim. Biophys. Acta, 321, 512-525 (1973)... 

Hydrogen ion concentration (pH) was the second criterion by which growth of the bacilli was established. Sulfuric acid is a natural metabolic by-product of sulfur oxidation by the acidophillic Thiobacillus thiooxidans (5). As sulfur is used, acid is built-up in the medium thus lowering the pH. Studies in this laboratory have shown that the bacteria grow well in a pH as low as 0.5. 

Deposition of elemental sulphur formed from sulphate Essential collaboration of at least two different microbial species occurs in the transformation of sulphate to S° in salt domes or similar sedimentary formations (see Ivanov, 1968). This transformation is dependent on the interaction of a sulphate reducer like Desulfovibrio desulfuricans, which transforms sulphate to H2S in its anaerobic respiratory metabolism, and an H2S oxidizer like Thiobacillus thioparus, which, under conditions of limited O2 availability, transforms H2S to S° in its respiratory metabolism (van den Ende van Gemerden, 1993). The collaboration of these two physiological types of bacteria is obligatory in forming S° from sulphate because sulphate reducers cannot form S° from sulphate, even as a metabolic intermediate. It should be noted, however, that the sulphate reducers and H2S oxidizers are able to live completely independent of each other as long as the overall formation of S° from sulphate is not a requirement. 

Lundgren, D.G., 1975. Microbiological problems in strip mine areas relationship to the metabolism of Thiobacillus ferrooxidans. Ohio J. Sci., 75 280—287. 

Tabita, R. and Lundgren, D.G., 1971a. Heterotrophic metabolism of the chemolitho-trophic Thiobacillus ferrooxidans. J. Bacteriol., 108 334—342. 

Tuovinen, O.H., Kelly, B.C. and Nicholas, D.J.D., 1976. Enzymic comparison of the inorganic sulfur metabolism in autotrophic and heterotrophic Thiobacillus ferrooxidans. Can. J. Microbiol., 22 109—113. 

Liibben M, Kolmerer B, Saraste M (1992) On archaebacterial terminal oxidase combines core structures of two mitochondrial respiratory complexes. EMBO J 11 805-812 Lundgren DG, Silver M (1980) Ore leaching by bacteria. Annu Rev Microbiol 34 263-283 Lyric RM, Suzuki I (1970a) Enzyme involved in the metabolism of thiosulfate by Thiobacillus thioparus III. Properties of thiosulfate-oxidizing enzyme and proposed pathway of thiosulfate oxidation. Can J Biochem 48 355-363... 

Takai M, Kamimura K, Sugio T (2001) A new iron oxidase from moderately thermophilic iron-oxidizing bacterium strain TI-1. Eur J Biochem 268 1653-1658 Takakuwa S (1976) Studies on the metabolism of a sulfur-oxidizing bacterium XI. Electron transfer and the terminal oxidase system in sulfite oxidation of Thiobacillus thiooxidans. Plant Cell Physiol 17 103-110... 

Of all bacterial GDH s, only the one from Thiobacillus novellus is strongly affected by a purine nucleotide, AMP, but in a fashion which is distinct from that in which animal enzymes are regulated (S3). Since few regulatory features have been established for bacterial enzymes, it is unlikely that GDH constitutes a major point of control of nitrogen metabolism in these organisms. 

Other autotrophic organisms include Thiobacillus and Ferrobacillus which are both acidophilic. The acidophilic Thiobacillus thiooxidans was first described in 1922 and has been studied for many years. It is able to oxidize elementary sulphur with the production of sulphuric acid, pH values down to 1.0 or less being reported. T. thiooxidans can metabolize at pH values below 1.0 and can even survive values close to 0, although the pH optimum for its growth is near 3.5. A closely related species, T. fer-... 

Many different groups of bacteria, including Bacillus, Pseudomonas, and Thiobacillus, are capable of denitrification. The primary biochemical pathways for organic substrate oxidation by denitri-fiers are similar to that described for aerobic catabolism. Because most of the denitrifiers are facultative anaerobes, they possess a functional TCA cycle that allows them to metabolize substrates completely to carbon dioxide and water. Many denitrifiers do not produce extracellular enzymes required for hydrolysis of polymers thus, they generally rely on hydrolytic enzymes and fermenters to provide readily available substrates (Ljundahl and Erickson, 1985). 

The metabolism of certain aerobic bacteria produces strong acids, which can accelerate corrosion. The best known example are bacteria of the Thiobacillus family that are able to oxidize sulfides or sulfur compounds into sulfuric acid. Certain organic acids produced by bacteria have the ability to form chelate complexes with dissolved metal ions, changing the thermodynamic conditions for corrosion (Chapter 2). In some cases the chelates may precipitate with electrolyte cations and form a film. 

Since its demonstration in photosynthetic organisms, the carboxylation enzyme has been demonstrated in E, coli and Thiobacillus. The physiological significance of this enzyme in nonphotosynthetic organisms is not clear, but its occurrence emphasizes that the carbon metabolism of photosynthesis is an enzymatic process distinct from the photochemical reaction. 

Acid producing bacteria (APB s) are those microorganisms whose metabolism results in the production of organic or inorganic acids. Examples of these organisms include Clostridium aceticum, that produces acetic acid, and Thiobacillus thiooxidans that produces sulfuric acid. Both of these organisms can contribute towards MIC of metal surfaces (Little et al, 1991). 

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