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Bioprocess and Biosystems Engineering Sep 2023In the wet flue gas desulfurization (WFGD) process, SO is adsorbed by alkaline liquor to produce alkaline wastewater containing sulfate and sulfite. Although the...
In the wet flue gas desulfurization (WFGD) process, SO is adsorbed by alkaline liquor to produce alkaline wastewater containing sulfate and sulfite. Although the traditional chemical treatment method can achieve a high removal rate, it consumes a large number of chemicals and yields a large number of low-value by-products. The biological treatment process is a greener and more environmentally friendly treatment method. The current work studies microbial flue gas desulfurization directly using sulfite as the electron acceptor in the reduction process. Desulfovibrio were obtained by isolation and purification, and their growth conditions in sulfite wastewater and desulfurization process conditions were investigated by intermittent and continuous experiments. The results of intermittent experiments indicated that the optimal growth conditions of Desulfovibrio were a temperature of 38 °C, a pH value of 8.0, a COD/SO of 2 and that the growth of bacteria would be inhibited at a pH above 9.0 or below 7.3. Furthermore, Desulfovibrio could grow in simulated wastewater with a high SO concentration of 8000 mg/L. The results of continuous experiments showed that the removal of sulfite and the recovery of elemental sulfur was realized by a micro-oxygen depletion process, and the removal rate of sulfite of 99%, the yield of elemental sulfur is more than 80% and can reach 90% under the condition of low influent concentration. The bacteria grew well at a temperature of 40 °C and a pH value of the influent water of 7.5. To ensure the treatment effect, the hydraulic retention time (HRT) should be more than doubled for each 1000 mg/L increase in the influent sulfite concentration under the same reflux ratio. When the influent sulfite concentration was 1000 mg/L, 2000 mg/L, 3000 mg/L, and 4000 mg/L, the corresponding HRT was 3.01 h, 6.94 h, 17.4 h, and 31.9 h, respectively. The dominant species in the reactor was Desulfovibrio bacteria at 63.9% abundance. This study demonstrated the feasibility of using sulfite as an electron acceptor for microbial desulfurization, which can optimize the initial process and provide the possibility of treating high-concentration sulfite wastewater.
Topics: Wastewater; Sewage; Waste Disposal, Fluid; Sulfites; Bacteria; Sulfur; Desulfovibrio
PubMed: 37418179
DOI: 10.1007/s00449-023-02895-0 -
Research in Microbiology 2020Mercury methylation converts inorganic mercury into the toxic methylmercury, and the consequences of this transformation are worrisome for human health and the...
Mercury methylation converts inorganic mercury into the toxic methylmercury, and the consequences of this transformation are worrisome for human health and the environment. This process is performed by anaerobic microorganisms, such as several strains related to Pseudodesulfovibrio and Desulfovibrio genera. In order to provide new insights into the molecular mechanisms of mercury methylation, we performed a comparative genomic analysis on mercury methylators and non-methylators from (Pseudo)Desulfovibrio strains. Our results showed that (Pseudo)Desulfovibrio species are phylogenetically and metabolically distant and consequently, these genera should be divided into various genera. Strains able to perform methylation are affiliated with one branch of the phylogenetic tree, but, except for hgcA and hgcB genes, no other specific genetic markers were found among methylating strains. hgcA and hgcB genes can be found adjacent or separated, but proximity between those genes does not promote higher mercury methylation. In addition, close examination of the non-methylator Pseudodesulfovibrio piezophilus C1TLV30 strain, showed a syntenic structure that suggests a recombination event and may have led to hgcB depletion. The genomic analyses identify also arsR gene coding for a putative regulator upstream hgcA. Both genes are cotranscribed suggesting a role of ArsR in hgcA expression and probably a role in mercury methylation.
Topics: Bacterial Proteins; Desulfovibrio; Desulfovibrionaceae; Gene Expression Regulation, Bacterial; Genome, Bacterial; Mercury; Methylation; Phylogeny
PubMed: 31655199
DOI: 10.1016/j.resmic.2019.10.003 -
Frontiers in Cellular and Infection... 2021Sulfate Reducing Bacteria (SRB), usually rare residents of the gut, are often found in increased numbers (called a SRB bloom) in inflammatory conditions such as...
Sulfate Reducing Bacteria (SRB), usually rare residents of the gut, are often found in increased numbers (called a SRB bloom) in inflammatory conditions such as Inflammatory Bowel Disease (IBD), pouchitis, and periodontitis. However, the underlying mechanisms of this association remain largely unknown. Notch signaling, a conserved cell-cell communication pathway, is usually involved in tissue development and differentiation. Dysregulated Notch signaling is observed in inflammatory conditions such as IBD. Lipolysaccharide and pathogens also activate Notch pathway in macrophages. In this study, we tested whether Desulfovibrio, the most dominant SRB genus in the gut, may activate Notch signaling. RAW 264.7 macrophages were infected with (DSV) and analyzed for the expression of Notch signaling pathway-related proteins. We found that DSV induced protein expression of Notch1 receptor, Notch intracellular domain (NICD) and p21, a downstream Notch target, in a dose-and time-dependent manner. DSV also induced the expression of pro-IL1β, a precursor of IL-1β, and SOCS3, a regulator of cytokine signaling. The gamma secretase inhibitor DAPT or Notch siRNA dampened DSV-induced Notch-related protein expression as well the expression of pro-IL1β and SOCS3. Induction of Notch-related proteins by DSV was not affected by TLR4 -IN -C34(C34), a TLR4 receptor antagonist. Additionally, cell-free supernatant of DSV-infected macrophages induced NICD expression in uninfected macrophages. DSV also activated Notch pathway in the human epithelial cell line HCT116 and in mouse small intestine. Thus, our study uncovers a novel mechanism by which SRB interact with host cells by activating Notch signaling pathway. Our study lays a framework for examining whether the Notch pathway induced by SRB contributes to inflammation in conditions associated with SRB bloom and whether it can be targeted as a therapeutic approach to treat these conditions.
Topics: Animals; Bacteria; Desulfovibrio; Mice; RAW 264.7 Cells; Receptor, Notch1; Signal Transduction; Sulfates
PubMed: 34336718
DOI: 10.3389/fcimb.2021.695299 -
Journal of Colloid and Interface Science Aug 2021The aim of this study is to explore the fate and mechanism of metal cations of biosorption in the Desulfovibrio vulgaris system (including bacterial cells and secreted...
The aim of this study is to explore the fate and mechanism of metal cations of biosorption in the Desulfovibrio vulgaris system (including bacterial cells and secreted loosely-bound extracellular polymeric substances (LB-EPS) and tightly-bound extracellular polymeric substances (TB-EPS)). The relative contribution of EPS (TB-EPS and LB-EPS) to the adsorption of three metal cations is much greater than that of bacterial cells, and the adsorption capacity of Pb on EPS (TB-EPS and LB-EPS) is much greater than that of Cu and Zn (Pb > Cu > Zn). The order of absorption capacity was as follows: LB-EPS > TB-EPS > bacterial cells, the adsorption contribution of EPS (including TB-EPS and LB-EPS) to Cu, Zn and Pb accounted for total adsorption capacity was 82%, 83% and 86%, respectively. It was suggested that LB-EPS was the first reaction barrier of immobilization metal cations before metal cations was able to pass through EPS and react with cells. The adsorption process was dominated by complexation and electrostatic interaction. The three-dimensional excitation-emission matrix (3D-EEM) identified two main fluorescence peaks of the aromatic and tryptophan protein-like substances in EPS. According to the synchronous fluorescence spectra, the tryptophan protein-like substances were gradually quenched with increased metal cations concentrations, which the quencher mechanism is dynamic quenching. The findings of this work are significant to reveal the fate of Cu, Zn and Pb during its sorption process onto Desulfovibrio vulgaris, and provide useful information of the interaction between Desulfovibrio vulgaris and its secreted EPS with metal cations.
Topics: Biopolymers; Desulfovibrio vulgaris; Extracellular Polymeric Substance Matrix; Lead; Sewage; Zinc
PubMed: 33852983
DOI: 10.1016/j.jcis.2021.03.152 -
Journal of Hazardous Materials Apr 2024Sulfur-containing substances in sewers frequently incur unpleasant odors, corrosion-related economic loss, and potential human health concerns. These observations are... (Review)
Review
Sulfur-containing substances in sewers frequently incur unpleasant odors, corrosion-related economic loss, and potential human health concerns. These observations are principally attributed to microbial reactions, particularly the involvement of sulfate-reducing bacteria (SRB) in sulfur reduction process. As a multivalent element, sulfur engages in complex bioreactions in both aerobic and anaerobic environments. Organic sulfides are also present in sewage, and these compounds possess the potential to undergo transformation and volatilization. In this paper, a comprehensive review was conducted on the present status regarding sulfur transformation, transportation, and remediation in sewers, including both inorganic and organic sulfur components. The review extensively addressed reactions occurring in the liquid and gas phase, as well as examined detection methods for various types of sulfur compounds and factors affecting sulfur transformation. Current remediation measures based on corresponding mechanisms were presented. Additionally, the impacts of measures implemented in sewers on the subsequent wastewater treatment plants were also discussed, aiming to attain better management of the entire wastewater system. Finally, challenges and prospects related to the issue of sulfur-containing substances in sewers were proposed to facilitate improved management and development of the urban water system.
Topics: Humans; Sulfur; Sulfur Compounds; Corrosion; Desulfovibrio; Sewage
PubMed: 38335612
DOI: 10.1016/j.jhazmat.2024.133618 -
Microbiological Research Jul 2024Increasing studies have focused on the relationship between Desulfovibrio bacteria (DSV) and host health in recent years. However, little is known about the mechanisms... (Review)
Review
Increasing studies have focused on the relationship between Desulfovibrio bacteria (DSV) and host health in recent years. However, little is known about the mechanisms by which DSV affects host health and the strategies to accurately regulate DSV numbers. This review mainly presents the relationship between DSV and host health, potential modulatory strategies, and the potential mechanisms affecting host health. Evidence suggests that DSV can both promote host health and induce the occurrence and development of disease, and these effects are closely related to its metabolites (e.g., HS and short-chain fatty acids) and biofilm. DSV abundance in the intestine is influenced by probiotics, prebiotics, diet, lifestyle, and drugs.
Topics: Desulfovibrio; Humans; Probiotics; Gastrointestinal Microbiome; Biofilms; Intestines; Prebiotics; Animals; Fatty Acids, Volatile; Hydrogen Sulfide; Diet
PubMed: 38663233
DOI: 10.1016/j.micres.2024.127725 -
Biofouling 2023Sulphate-reducing bacteria (SRB) are known to cause severe corrosion of steel structures in various industries, resulting in significant economic and environmental... (Review)
Review
Sulphate-reducing bacteria (SRB) are known to cause severe corrosion of steel structures in various industries, resulting in significant economic and environmental consequences. This review paper critically examines the impact of SRB-induced corrosion on steel, including the formation of SRB biofilms, the effect on different types of steel, and the various models developed to investigate this phenomenon. The role of environmental factors in SRB-induced corrosion, molecular techniques for studying SRBs, and strategies for mitigating corrosion are discussed. Additionally, the sustainability implications of SRB-induced corrosion and the potential use of alternative materials were explored. By examining the current state of knowledge on this topic, this review aims to provide a comprehensive understanding of the impact of SRB-induced corrosion on steel and identify opportunities for further research and development.
Topics: Biofilms; Steel; Corrosion; Desulfovibrio; Sulfates
PubMed: 38073525
DOI: 10.1080/08927014.2023.2284316 -
Microbiome Apr 2023Mangrove ecosystems are considered as hot spots of biogeochemical cycling, yet the diversity, function and coupling mechanism of microbially driven biogeochemical...
BACKGROUND
Mangrove ecosystems are considered as hot spots of biogeochemical cycling, yet the diversity, function and coupling mechanism of microbially driven biogeochemical cycling along the sediment depth of mangrove wetlands remain elusive. Here we investigated the vertical profile of methane (CH), nitrogen (N) and sulphur (S) cycling genes/pathways and their potential coupling mechanisms using metagenome sequencing approaches.
RESULTS
Our results showed that the metabolic pathways involved in CH, N and S cycling were mainly shaped by pH and acid volatile sulphide (AVS) along a sediment depth, and AVS was a critical electron donor impacting mangrove sediment S oxidation and denitrification. Gene families involved in S oxidation and denitrification significantly (P < 0.05) decreased along the sediment depth and could be coupled by S-driven denitrifiers, such as Burkholderiaceae and Sulfurifustis in the surface sediment (0-15 cm). Interestingly, all S-driven denitrifier metagenome-assembled genomes (MAGs) appeared to be incomplete denitrifiers with nitrate/nitrite/nitric oxide reductases (Nar/Nir/Nor) but without nitrous oxide reductase (Nos), suggesting such sulphide-utilizing groups might be an important contributor to NO production in the surface mangrove sediment. Gene families involved in methanogenesis and S reduction significantly (P < 0.05) increased along the sediment depth. Based on both network and MAG analyses, sulphate-reducing bacteria (SRB) might develop syntrophic relationships with anaerobic CH oxidizers (ANMEs) by direct electron transfer or zero-valent sulphur, which would pull forward the co-existence of methanogens and SRB in the middle and deep layer sediments.
CONCLUSIONS
In addition to offering a perspective on the vertical distribution of microbially driven CH, N and S cycling genes/pathways, this study emphasizes the important role of S-driven denitrifiers on NO emissions and various possible coupling mechanisms of ANMEs and SRB along the mangrove sediment depth. The exploration of potential coupling mechanisms provides novel insights into future synthetic microbial community construction and analysis. This study also has important implications for predicting ecosystem functions within the context of environmental and global change. Video Abstract.
Topics: Methane; Nitrogen; Microbiota; Desulfovibrio; Sulfur; Sulfides; Geologic Sediments
PubMed: 37020239
DOI: 10.1186/s40168-023-01501-5 -
World Journal of Microbiology &... Jun 2021Sulfate-reducing bacteria (SRB) are culprits for microbiologically influenced corrosion, and biofilms are believed to play essential roles in the corrosion induced by...
Sulfate-reducing bacteria (SRB) are culprits for microbiologically influenced corrosion, and biofilms are believed to play essential roles in the corrosion induced by SRB. However, little is known about the regulation of SRB biofilms. Quorum sensing signal molecules acyl-homoserine lactones (AHLs) and autoinducer-2 (AI-2) regulate biofilm formation of many bacteria. In this study, the production of AHLs and AI-2 by one SRB strain, Desulfovibrio sp. Huiquan2017, was detected, and the effect of exogenous AI-2 on bacterial biofilm formation was discussed. It was found that the cell-free supernatants of Desulfovibrio sp. Huiquan2017 induced luminescence in a ∆luxS mutant strain Vibrio harveyi BB170, indicating the production of functional AI-2 by the bacterium. In the presence of exogenous AI-2, the growth of Desulfovibrio sp. Huiquan2017 and early biofilm formation were not affected, but the later stage of biofilm development was inhibited significantly. The biofilms became looser, smaller, and thinner, and contained less bacteria and extracellular polymeric substances (EPS). The inhibition effect of AI-2 on the biofilm development of Desulfovibrio sp. Huiquan2017 was mainly achieved through reducing the amount of EPS in biofilms. These findings shed light on the biofilm regulation of SRB.
Topics: Agrobacterium tumefaciens; Bacterial Proteins; Biofilms; Corrosion; Desulfovibrio; Extracellular Polymeric Substance Matrix; Homoserine; Lactones; Quorum Sensing; Vibrio
PubMed: 34170406
DOI: 10.1007/s11274-021-03071-w -
Scientific Reports May 2020Sedimentary pyrite (FeS) is commonly thought to be a product of microbial sulfate reduction and hence may preserve biosignatures. However, proof that microorganisms are...
Sedimentary pyrite (FeS) is commonly thought to be a product of microbial sulfate reduction and hence may preserve biosignatures. However, proof that microorganisms are involved in pyrite formation is still lacking as only metastable iron sulfides are usually obtained in laboratory cultures. Here we show the rapid formation of large pyrite spherules through the sulfidation of Fe(III)-phosphate (FP) in the presence of a consortium of sulfur- and sulfate-reducing bacteria (SRB), Desulfovibrio and Sulfurospirillum, enriched from ferruginous and phosphate-rich Lake Pavin water. In biomineralization experiments inoculated with this consortium, pyrite formation occurred within only 3 weeks, likely enhanced by the local enrichment of polysulfides around SRB cells. During this same time frame, abiotic reaction of FP with sulfide led to the formation of vivianite (Fe(PO)·8HO) and mackinawite (FeS) only. Our results suggest that rates of pyritization vs. vivianite formation are regulated by SRB activity at the cellular scale, which enhances phosphate release into the aqueous phase by increased efficiency of iron sulfide precipitation, and thus that these microorganisms strongly influence biological productivity and Fe, S and P cycles in the environment.
Topics: Campylobacteraceae; Desulfovibrio; Iron; Lakes; Microbial Consortia; Oxidation-Reduction; Phosphates; Sulfates; Sulfides; Sulfur
PubMed: 32427954
DOI: 10.1038/s41598-020-64990-6