Sulphide bacterial

Hydrogen sulphide and sulphur dioxide are also usually the result of pollution sometimes they are produced by the interaction of two contaminants, but sometimes bacterial action may be contributory. Both gases may initiate or accelerate corrosion of most metals. 

Bacterial activity often plays a major part in determining the corrosion of buried steel. This is particularly so in waterlogged clays and similar soils, where no atmospheric oxygen is present as such. If these soils contain sulphates, e.g. gypsum and the necessary traces of nutrients, corrosion can occur under anaerobic conditions in the presence of sulphate-reducing bacteria. One of the final products is iron sulphide, and the presence of this is characteristic of attack by sulphate-reducing bacteria, which are frequently present (see Section 2.6). 

Pitcher MCL, Cummings JH. 1996. Hydrogen sulphide A bacterial toxin in ulcerative colitis Gut 39 1-4. 

Pitcher MCL, Beatty ER, Cummings JH Salicylates inhibit bacterial sulphide production within the colonic lumen in ulcerative colitis. Gut 1995 37 A15. 

Bacterial pigments. Some bacteria commonly found in caries lesions are known to produce pigments. For example, the black staining of plaque is related with Actinomyces (Slots, 1974), but its chemical nature remains unknown. Black pigmented Prevotella produces both iron sulphide and heme pigments (Shah et ah, 1979). In addition, Propionibacterium forms porphyrins (Lee et al., 1978). Bacterial iron-binding peptides, which can contribute to discoloration, increase in the saliva of subjects with a high caries frequency (Nordh, 1969). 

Active Site Structure of Rubredoxin There are several non-heme iron-sulphur proteins that are involved in electron transfer. They contain distinct iron-sulphur clusters composed of iron atoms, sulphydryl groups from cysteine residues and inorganic or labile sulphur atoms or sulphide ions. The labile sulphur is readily removed by washing with acid. The cysteine moieties are incorporated within the protein chain and are thus not labile. The simplest type of cluster is bacteria rubredoxin, (Cys-S)4 Fe (often abbreviated FelSO where S stands for inorganic sulphur), and contains only non labile sulphur. It is a bacterial protein of uncertain function with a molecular weight of 6000. The single iron atom is at the centre of a tetrahedron of four cysteine ligands (Fig.). 

Phoenix, V.R., Renaut, R.W., Jones, B. and Ferris, F.G. (2005) Bacterial S-layer preservation and rare arsenic-antimony-sulphide bioimmobilization in siliceous sediments from Champagne pool hot spring, Waiotapu, New Zealand. Journal of the Geological Society, 162(2), 323-31. 

Early decay Autolysis and bacterial decay characterized by methane, hydrogen sulphide, hydrogen, and carbon dioxide production... 

Bacterial reduction of sulfate in an anaerobic environment with large isotope fractionation between the residual sulphate and the sulphide is the source of sulphur and sulphide in many deposits. The recognition that many sulphur... 

Aerobic mineral oxidation resulting in mineral degradation and product mobilization Aerobic bacterial oxidation of elemental sulphur (S°), of various mineral sulphides such as pyrite (FeS2), chalcopyrite (CuFeS2), arsenopyrite (FeAsS), sphalerite (ZnS), cobalt sulphide (CoS) and nickel sulphide (NiS) to corresponding metal sulphates, and of uraninite (UO2) to U02 are examples in which oxidizable minerals undergo dissolution of one or more of their constituents, which are thus mobilized (see Ehrlich, 2002a). 

Metal sulphides Sulphide produced in bacterial sulphate respiration can precipitate heavy metal ions from solution when the sulphide concentration is in excess of that demanded by the solubility product of the... 

Byman (1977) detected volatile sulphur species in the headspace gas over sulphides oxidising in vitro. The major gases detected were, initially, carbonyl sulphide and carbon disulphide. As the experiments continued dimethyl sulphide, (CH,)2S was detected, presumably as the result of bacterial action. 

In summary, the sulphur gases most likely to be related to sulphide mineralisation in the natural environment are CS2, COS, H2S and (CHj)2S. Many chemical reactions can occur between the time a sulphur compound (volatile or non-volatile) leaves a deposit and the time a volatile sulphur compound appears near the ground surface above the deposit. Bacterial action probably plays a large role in the formation of sulphur gases as they react with minerals in the deposit, with bedrock, with groundwater and with soil en route to the surface. Therefore, while gaseous sulphur compounds over or peripheral to sulphide mineralisation may be related to the mineralisation, the compounds may or may not have originated directly from the mineralisation. 

Torma, A.E. and Subramanian, K.N., 1974. Selective bacterial leaching of a lead sulphide concentrate. Int. J. Miner. Process., 1 125—134. 

Khalid, A.M. and Ralph, B.J., 1977. The Leaching behaviour of various zinc sulphide minerals with three Thiobacillus species. Conference Bacterial Leaching. GBF Monograph Series, No. 4 pp. 165—173. 

A possible model of an Archaean mat community is one in which sea water rich in SO " is reduced in a system that is only occasionally open to ambient water inflow. In such a setting, partly open-system fractionation occurs, giving a moderately symmetric isotopic distribution in sulphides (fig. 4E of Ohmoto 1992). The dataset from the Spring Valley and Shavi Members, both in shape and range, is thus here interpreted as probable evidence for a nearly closed-system fractionation in a bacterial mat flushed by sea water that was relatively rich in sulphate, with water sulphate possibly around 3 5%o. However, Archaean seawater 5 S remains unknown. The ratio is thought to have been not far from 0%o, but this inference is lightly based on a few sulphate deposits that may not be primary the ratio could have been as heavy as 10-15%o (Kakegawa et al. 1998). 

To summarize, the isotopic and textural evidence collectively implies the activity in the Belingwe belt of a variety of prokaryotic processes (1) sulphate reduction and possibly photosynthetic sulphide oxidation (2) operation of rubisco both in cyanobacterial stromatolites (as expected) but also possibly in non-photosynthetic sulphur-bacterial mats (3) oxygenic photosynthesis (in stromatolites) (4) methanogenesis and methane oxidation. Most probably, other sulphur-based metabolic reactions (e.g. dissim-ilatory sulphate reduction) were also taking place. This complexity is consistent with the relative timing of the metabolic phylogeny deduced from rRNA studies (Woese 1987 Pace 1997). 

---