Sulfate-reducing Bacterial Research Articles

Characterization of Desulfovibrio sp. isolated from some lowland paddy field soils of Burkina Faso

In a wetland ecosystem such as lowland ricefields, the anaerobic mineralization of organic matter is a key mechanism for nutrient recycling (Jørgensen 1982; Freney et al. 1982). In the process which involves several bacterial groups, sulfate reducers (Watanabe and Furusaka 1980; Widdel 1988; Ouattara and Jacq 1992; Nozoe 1997), methanogens (Asakawa and Hayano 1995; Dianou et al. 1997), sulfur and ferric ion reducers (Jacq et al. 1991) become active when the soil becomes anoxic (Amstrong 1969). Sulfate reducers are common in flooded soils (Watanabe and Furusaka 1980; Widdel 1988; Furusaka et al. 1991). Reported densities in rice soils ranged from 103 to 105 g-1 dry soils in Asia (Watanabe and Furusaka 1980) and from 102 to 109 g-1 dry soil in Sénégal (Ouattara and Jacq 1992). Among the sulfate reducers, the “classical” Desulfovibrio species are known to oxidize typical fermentation products such as hydrogen, lactate, pyruvate, and dicarboxylic acids (Widdel 1988). So far, data on the isolation and characterization of sulfate-reducing bacterial (SRB) strains from African rice paddy field soils study have been very limited.

The effect of alkaline pH conditions on a sulphate reducing consortium from a Danish district heating plant

This study demonstrated that a non‐alkaliphilic sulphate reducing bacterial (SRB) consortium could survive the alkaline environment in the circulation water of a Danish District Heating Plant. The plant was experiencing corrosion, and SRB were postulated to be responsible. A bacterial consortium containing mesophilic SRB was enriched in vials inoculated with the plant circulation water. A batch experiment illustrated the ability of the SRB to survive a pH of 10.5. The same SRB produced sulphide at a pH of 9.3, when the pH in the batch vials was lowered by other bacteria present in the consortium. Another experiment demonstrated that, when protected in a biofilm, the same SRB consortium produced sulphide at a bulk fluid pH of 10.2. These results could be implemented as part of a SRB control strategy in the field.

Process measurement and phylogenetic analysis of the sulfate reducing bacterial communities of two contrasting benthic sites in the upper estuary of the Great Ouse, Norfolk, UK

Seasonal measurements of sedimentary sulfate reduction at a freshwater site (site 1) and a brackish/marine site (site 4) in the upper estuary of the Great Ouse, Norfolk, UK revealed very similar integrated annual rates of sulfate reduction: 5.3 and 3.7 mol sulfate m −2 year −1, respectively, but two distinctly different seasonal cycles. At site 4 sulfate reduction followed a seasonal pattern with summer maxima and winter minima, suggesting temperature dependence, but in contrast at site 1 there was no distinct seasonal cycle. Use of 16S rRNA-targeted oligonucleotide probes to investigate the active sulfate reducing bacterial (SRB) populations suggested that populations of SRB remained relatively constant at site 4 throughout the year. However, at site 1 distinct peaks in signal from a Desulfovibrio spp.-targeted probe were measured which corresponded with peaks in sulfate reduction activity. In addition, sedimentary profiles suggested that both sulfate reduction activity and active SRB populations peaked at 0–5 cm into the sediment at site 1 but deeper into the sediment at 9–10 cm at site 4. The results indicate that SRB population dynamics are more complex than process measurements would suggest.

Interactive effects of temperature and cf4 o‐ cf3 cresol co‐disposal on the methanogenic fermentation of refuse

The influence of temperature on both o‐cresol biodegradation and methanogenic refuse decomposition was investigated. Maximum o‐cresol attenuation was recorded from 25 to 37°C. Mesophilic and thermophilic sulphate‐reducing bacterial (SRB) activity was observed, but thermophilic methanogenesis was not recorded. Maximum methane release and SRB activity was recorded at 25–37°C, and ≥30°C, respectively. Optimum conditions for acetate utilization were similar to those for methanogenesis, but propionate degradation apparently depended on SRB activity. Propionate degradation was recorded under thermophilic conditions, even in the absence of methanogenesis, although the optimum temperature was 37°C. When SRB were inhibited, at temperatures ≤25°C, no significant propionate catabolism was observed.

Use of multi-stage continuous culture systems to investigate the effects of temperature on the methanogenic fermentation of cellulose-degradation intermediates

A three-stage continuous culture system was used to segregate the component physiological groups of an anaerobic cellobiose-degrading association enriched and isolated from a landfill site. The optimum temperatures for methanogenesis were 30-35°C, although differences apparent in Vessels B and C at lower temperatures suggested the presence of distinct populations in the two vessels. There was no evidence of thermophilic methanogenic activity. Sulphate-reducing bacterial (SRB) activity was less affected by temperature perturbation, and there was significant SRB activity at 55°C.