Bacteria sulphur oxidizing

Some bacteria are involved directly in the oxidation or reduction of metal ions such as iron and manganese. Some microbes produce organic acids such as formic and succinic acid or mineral acids such as sulfuric acid. Some bacteria can oxidize sulphur or sulfide to sulfate or reduce sulfates to hydrogen sulfide (H2S) (41). 

The sulphur oxidizing bacteria can produce up to nearly 10% sulfuric acid, which is highly corrosive to metals, coatings, ceramics, and concrete. Other bacteria can produce formic and succinic acids, which are also harmful especially to some organic coatings (52). 

Phase 1 is the chemical corrosion phase, where no bacteria are involved. In this phase, due to the combined effect of hydrogen sulfide and atmospheric carbon dioxide, concrete s pH is highly reduced to less than 10. In phase 2, the first stage of microbial succession starts, where a certain species of SOB neutrophilic sulphur-oxidizing bacteria (NSOM) further reduces pH, resulting in the... 

P. Bos, J.G. Kuenen. Microbiology of sulphur-oxidizing bacteria. In the Proceedings of Microbial Corrosion, The Metals Society, London, 1983. 

Of the sulphur bacteria, which oxidize hydrogen sulphide, the genera Beggiatoa and Thiothrix are of significance for drinking water and process water supplies. 

One answer tothe mystery of how the oxidation and reduction can be so intense at a roll front was given by Rackley, w ho demonstrated that sulphur-oxidizing and. sulphur-reducing bacteria can provide the driving force for a galvanic cell that controls the geochemical reactions. This seems to be the case where iron sulphide dominates the minerals that are precipitated in the mineralized ground. 

Ramfrez M, Ferndndez M, Granada C, Le Borgne S, Gomez JM, Cantero D (2011) Biofiltration of reduced sulphur compounds and community analysis of sulphur-oxidizing bacteria. Bioresour Technol 102 4047-4053... 

G. Cragnolino and O. H. Tuovinen, The role of sulphate reducing and sulphur oxidizing bacteria in the localized corrosion of iron-base alloys—a review, Int. Biodeterioration 20 9-26 (1984). 

MOSER U.S. and OLSEN R.V. 1953. Sulphur oxidation in four soils as influenced by soil moisture tension and sulphur bacteria. 

Smith NA, DP Kelly (1988) Isolation and physiological characterization of autotrophic sulphur bacteria oxidizing dimethyl disulphide as sole source of energy. J Gen Microbiol 134 1407-1417. 

The element has a definite fertilising action 2 which is exerted in two ways (1) It supplies sulphuric acid by bacterial oxidation, the presence of the acid increasing the availability of certain mineral constituents in the soil, such as alkalis, ferric oxide, alumina and phosphates. (2) It facilitates the work of the ammonia and nitrifying bacteria, thus placing larger supplies of nitrogen at the disposal of the plants. But although such action may be beneficial in some soils it is equally harmful in others, and sulphur should not be applied to a soil already acid.3... 

The electron localized on the particle Q is subsequently used, through a complicated chain of chemical reactions, to reduce C02 to the carbohydrates (CH20)6, while the "hole localized on the particle C+ is used to oxidize some certain substrate, say hydrogen sulphide to sulphur. This results in the regeneration of the active centre C-P-J-A-Q. The overall chemical reaction of photosynthesis in purple bacteria can be thus written as... 

DMSP in phytoplankton was initially proposed to function as an osmolyte (Vairavamurty et al. 1985). Over the years we now have evidence for its role in other processes such as for cryopreser-vation (Kirst et al. 1991), as a deterrent against grazing (Dacey and Wakeham 1986 Wolfe and Steinke 1996) and against bacteria (Wolfe et al. 1997). In the recent past the anti-oxidant role of DMSP is becoming more popular (Sunda et al. 2002). Factors controlling DMSP production, its conversion to DMS, fate of DMSP and DMS sulphur in the marine environment are well documented in the review by Stefels et al. (2000) and in the present issue. 

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. 

The main reaction responsible for marble decay and damage to monuments is therefore the sulphation which occurs on the surface of these materials. Oxidation of SO2 to SO3 occurs by catalytic action due to surface impurities such as FeaO. , soot, colloidal deposits, CaS04 2H 0 already formed, humidity and also to sulphur oxidising bacteria. 

It is self-evident that the oxidation of sulphide minerals entails the consumption of oxygen. The initial source is molecular oxygen from the atmosphere but this must pass into solution in groundwater or soil solutions before any reaction with sulphides is possible. Interstitial air in soils, overburden or porous rocks forms an intermediate reservoir of oxygen between buried sulphides and the free atmosphere. The oxidation may be entirely chemical or may be enhanced by the microbial action of bacteria such as Thiohacillus thiooxidans. The oxidation of sulphides leads to the production of sulphuric acid, which will be neutralised by any available carbonates with the release of gaseous carbon dioxide into the subsurface surroundings and ultimately into the atmosphere. 

The existence in the Archaean of sulphate-reducing bacteria, producing a spread in S isotopes around b S = 0 5%o has long been accepted (e.g. Goodwin et al. 1976 Shen et al. 2001). Sulphate would have come from ambient water, with a component supply of metals and other nutrients from hydrothermal sources, as shown by the REE (Table 1). In modem microbial mats, sulphate-reducing bacteria extract sulphur from sea water, fractionating it by an amount that depends on the efficiency and rate of extraction. Conversely, sulphide-oxidizers reverse the process. 

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