Bacteria sulfate reduction

Hammack, R. W. and H. M. Edenbom. 1991. The removal of nickel from mine waters using bacteria sulfate reduction. In W. Oaks and J. Bowden, Eds. Proceedings of the 1991 National Meeting of the American Society of Surface Mining and Reclamation Vol. 1. Princeton, WV, pp. 97-107. 

In water containing sulfate, the use of the electrolysis protection process with low water consumption can sometimes result in the formation of small amounts of HjS, which is detectable by the smell. Sulfate reduction occurs through the action of bacteria in anaerobic areas (e.g., in the slurry zone of the tank). 

Dissimilatory sulfate reduction (SO - - H2S) Sulfate-reducing bacteria... 

This key enzyme of the dissimilatory sulfate reduction was isolated from all Desulfovibrio strains studied until now 135), and from some sulfur oxidizing bacteria and thermophilic Archaea 136, 137). The enzymes isolated from sulfate-reducing bacteria contain two [4Fe-4S] clusters and a flavin group (FAD) as demonstrated by visible, EPR, and Mossbauer spectroscopies. With a total molecular mass ranging from 150 to 220 kDa, APS reductases have a subunit composition of the type 012)32 or 02)3. The subunit molecular mass is approximately 70 and 20 kDa for the a and )3 subunits, respectively. Amino-acid sequence data suggest that both iron-sulfur clusters are located in the (3 subunit... 

Hydrogen sulfide is a well known general metabolite produced on sulfate reduction by certain bacteria. Moreover, organic forms of sulfur can give rise to HS , hence H2S in certain bacteria. Thus, cysteine desulfhydrase (EC 4.4.1.1, cystathionine y-lyase) converts L-cysteine to H2S, pyruvate, and NH3. This enzyme shows a requirement for pyridoxal phosphate and the unstable ami-noacrylic acid is an intermediate (Equation 1) in the reaction ... 

Chapelle, F. H. and D. R. Lovley, 1992, Competitive exclusion of sulfate reduction by Fe(III)-reducing bacteria a mechanism for producing discrete zones of high-iron ground water. Ground Water 30, 29-36. 

Fermentation may take place in the three major microbial subsystems of a sewer, i.e., the wastewater, the biofilm and the sediments (Figure 3.2). Sulfate-reducing bacteria are slow growing and are therefore primarily present in the biofilm and in the sediments, where sulfate from the wastewater may penetrate (Nielsen and Hvitved-Jacobsen, 1988 Hvitved-Jacobsen et al., 1998 Bjerre et al., 1998). However, as a result of biofilm detachment, sulfate reduction may, to some minor extent, take place in the wastewater. Methanogenic microbial activity normally requires absence of sulfate — or at least a low... 

Sulfate is typically found in all types of wastewater in concentrations greater than 5-15 gS nr i.e., in concentrations that are not limiting for sulfide formation in relatively thin biofilms (Nielsen and Hvitved-Jacobsen, 1988). In sewer sediments, however, where sulfate may penetrate the deeper sediment layers, the potential for sulfate reduction may increase with increasing sulfate concentration in the bulk water phase. Under specific conditions, e.g., in the case of industrial wastewater, it is important that oxidized sulfur components (e.g., thiosulfate and sulfite) other than sulfate may act as sulfur sources for sulfate-reducing bacteria (Nielsen, 1991). 

The temperature dependency of the sulfate reduction rate for single sulfate-reducing bacteria is high, corresponding to a temperature coefficient, a, of about 1.13, i.e., a change in the rate with a factor Q10 = 3.4 per 10°C of temperature increase. Because diffusion of substrate into biofilms or sediments is typically limiting sulfide formation, the temperature coefficient is reduced to about... 

The cycle of iron solubilization will continue as long as bacteria and/or plants produce organic ligands.The cycle will stop when sulfate reduction rates are high and organic ligand production is low. At this point soluble hydrogen sulfide reacts with Fe(II) to form sulfide minerals. The iron cycle shown in Fig. 10.15 for salt marsh sediments may also occur in other marine sedimentary systems. 

This lack of a concentration dependence contrasts with the sulfur isotope literature, which suggests that sulfur isotope fractionation induced by sulfate reduction decreases as the sulfate concentration decreases below 0.2 mmol/L (Canfield 2001 Habicht et al. 2002). This difference may reflect differences between S(VI) and Se(VI) reduction pathways or possible adaptations of bacteria to low Se concentrations, but at present no clear explanation has emerged. 

Marschall C, Frenzel P, Cypionka H. 1993. Influence of oxygen on sulfate reduction and growth of sulfate-reducing bacteria. Arch Microbiol 159 168-73. 

Naturally occurring snlfides in sediments and euxinic waters are commonly depleted in by np to 70%c (Jprgensen et al. 2004), far beyond the apparent capabilities of sulfate reducing bacteria. As has been shown above, most of the sulfide produced by sulfate reduction in sediments is reoxidized, often via compounds in which snlfm has intermediate oxidation states that do not accnmnlate, bnt... 

A large number of ferredoxin-dependent enzymes have been identified in bacteria . Flavodoxin will replace ferredoxin in most of these. Among the biochemical processes in which these proteins function are nitrogen fixation, hydrogen production and sulfate reduction. 

Microbial mat formation may also stimulate metal removal through sulfate reduction. Barnes, Scheeren Buisman (1994) have developed a process that specifically uses sulfate-reducing bacteria to treat metal-contaminated groundwater. In this process, as groundwater is pumped through the water treatment plant, sulfide produced by sulfate-reducing bacteria precipitates the metals in the water. Metal concentrations in the treated water were reportedly reduced to fig/l quantities and the water was suitable for release into the environment. 

Cysteine not only is an essential constituent of proteins but also lies on the major route of incorporation of inorganic sulfur into organic compounds.443 Autotrophic organisms carry out the stepwise reduction of sulfate to sulfite and sulfide (H2S). These reduced sulfur compounds are the ones that are incorporated into organic substances. Animals make use of the organic sulfur compounds formed by the autotrophs and have an active oxidative metabolism by which the compounds can be decomposed and the sulfur reoxidized to sulfate. Several aspects of cysteine metabolism are summarized in Fig. 24-25. Some of the chemistry of inorganic sulfur metabolism has been discussed in earlier chapters. Sulfate is reduced to H2S by sulfate-reducing bacteria (Chapter 18). The initial step in assimilative sulfate reduction, used by... 

Sulfate Reduction. Dissimilatory sulfate reduction, anaerobic respiration with sulfate as the terminal electron acceptor, is performed by relatively few genera of bacteria (84). Many bacteria and algae are able to... 

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