The bioenergetics mechanisms and applications of sulfate-reducing bacteria in remediation of pollutants in drainage: A review.

Immobilizing of heavy metals in sediments contaminated by nonferrous metals smelting plant sewage with sulfate reducing bacteria and micro zero valent iron

Hydrogen (H2) metabolism has attracted considerable interest because the activities of H2-producing and consuming microbes shape the global H2 cycle and may have vital relationships with the global cycling of other elements. There are many pathways of microbial H2 emission and consumption which may affect the structure and function of microbial communities. A wide range of microbial groups employ H2 as an electron donor to catalyze the reduction of pollutants such as organohalides, azo compounds, and trace metals. Syntrophy coupled mutualistic interaction between H2-producing and H2-consuming microorganisms can transfer H2 and be accompanied by the removal of toxic compounds. Moreover, hydrogenases have been gradually recognized to have a key role in the progress of pollutant degradation. This paper reviews recent advances in elucidating role of H2 metabolism involved in syntrophy and hydrogenases in environmental bioremediation. Further investigations should focus on the application of bioenergy in bioremediation to make microbiological H2 metabolism a promising remediation strategy.

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Function of Biohydrogen Metabolism and Related Microbial Communities in Environmental Bioremediation.

The undesired sulfur cycle derived by microbial population can ultimately causes the serious problems of sewerage systems. However, the microbial community characters under dynamic environment factors in actual sewerage system is still not enough. This current study aimed to character the distributions and compositions of microbial communities that participate in the sulfur cycle under the dynamic environmental conditions in a local sewerage system. To accomplish this, microbial community compositions were assessed using 454 high-throughput sequencing (16S rDNA) combined with dsrB gene-based denaturing gradient gel electrophoresis. The results indicated that a higher diversity of microbial species was present at locations in sewers with high concentrations of H2S. Actinobacteria and Proteobacteria were dominant in the sewerage system, while Actinobacteria alone were dominant in regions with high concentrations of H2S. Specifically, the unique operational taxonomic units could aid to characterize the distinct microbial communities within a sewerage manhole. The proportion of sulfate-reducing bacteria, each sulfur-oxidizing bacteria (SOB) were strongly correlated with the liquid parameters (DO, ORP, COD, Sulfide, NH3-N), while the Mycobacterium and Acidophilic SOB (M&A) was strongly correlated with gaseous factors within the sewer, such as H2S, CH4, and CO. Identifying the distributions and proportions of critical microbial communities within sewerage systems could provide insights into how the microbial sulfur cycle is affected by the dynamic environmental conditions that exist in sewers and might be useful for explaining the potential sewerage problems.

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Microbial Character Related Sulfur Cycle under Dynamic Environmental Factors Based on the Microbial Population Analysis in Sewerage System.

Sulfate-reducing bacteria detection based on the photocatalytic property of microbial synthesized ZnS nanoparticles.

The biogenic production of hydrogen sulfide is a serious problem associated with wastewater treatment. The aim of this study was to investigate the inhibitory effect of nitrate on the dynamics of sulfate-reducing bacteria (SRB) community in a laboratory-scale wastewater reactor, originating from a denitrifying plant using activated sludge. For this purpose, denaturing gradient gel electrophoresis (DGGE) analysis targeting the dsrB (dissimilatory sulfite reductase) gene was used in combination with chemical analyses and measurement of oxidation and reduction potential (ORP). The reactors were initially dosed with 1.0 and 4.0 g/L potassium nitrate and anaerobically incubated for 490 h. Addition of 4.0 g/L nitrate to the reactor was associated with a prolonged inhibition (over 300 h, i.e., 12.5 days) of sulfate reduction and this was consistent with a rapid decrease in ORP associated with nitrate depletion. The DGGE analysis revealed that nitrate addition remarkably attenuated a distinct group of dsrB related to Desulfovibrio, whereas other dsrB groups were not influenced. Furthermore, another sulfate reduction by Syntrophobacter in the later stages of the incubation period occurred in both reactors (regardless of the nitrate concentration), suggesting that different SRB groups are associated with sulfate reduction at different stages of the wastewater treatment process.

Genus-specific and phase-dependent effects of nitrate on a sulfate-reducing bacterial community as revealed by dsrB-based DGGE analyses of wastewater reactors.

Kouhei Mizuno

Papers

Genus-specific and phase-dependent effects of nitrate on a sulfate-reducing bacterial community as revealed by dsrB-based DGGE analyses of wastewater reactors.