Sulfate-reducing Bacteria Research Articles

Microbial Diversity in Hot Spring Soil Microbiome

Hot springs are natural habitats for thermophilic and hyperthermophilic microorganisms with optimal growth temperatures. This study was conducted using a metagenomic approach to analyze the microbial communities of Nglimut hot spring soils, Mount Ungaran. This study used an exploratory observational method. A total of ten samples of hot spring sediment soil were taken purposively in Nglimut hot spring, Mount Ungaran. A total of 600 grams of hot spring sediment soil samples were used for chemical analysis and 50 grams of samples for metagenomic analysis based on 16S rRNA V3-V4 gene marker regions. The total microbiota sequences analyzed in this study were 103,889 OTUs, consisting of 98,603 Bacteria OTUs and 5,286 Archaea OTUs. At the phylum level, all DNA sequences of soil microbiota bacteria identified 53 phyla, dominated by Proteobacteria (19.42%), Chloroflexi (17.21%), Nitrospirota (13.76%), Bacteroidota (7.67%) and Firmicutes (7.33%). At the order level, 305 bacterial orders were found, dominated by Nitrospirales (12.35%), Burkholderiales (7.99%), Rhizobiales (5.77%), Ignavibacteriales (4.06), and Anaerolineales (3.92%). A total of nine archaea phyla were identified in the hot spring soil, dominated by Crenarchaeota (85.13%), Nanoarchaeota (7.13%) and Halobacterota (5.58%). At the order level, 15 archaea orders were identified, dominated by Nitrosopumilales (64.08%), Nitrososphaerales (14.39%), Woesearchaeales (7.24%), Bathyarchaeia (6.15%), and Methanosarciniales (5.07%). The bacteria that dominate the soil of hot springs are bacteria that can survive at high temperatures (thermophilic) and are able to utilize sulfur. The presence of archaea in hot spring soils helps increase the activity of sulfate-reducing bacteria in sulfur-containing soils.

On-Site Trial Study of Denitrification to Suppress Sulfate-Reducing Bacteria (SRB) in Polymer Flooding Wastewater

Sulfate-reducing bacteria (SRB) is a common group of harmful bacteria in oilfield production, capable of reducing oxidized sulfur compounds such as sulfates (SO42-, SO32-) to sulfide ions using various organic materials including petroleum and natural gas as carbon sources. This metabolic process by SRB poses significant hazards to oilfield operations: SRB-induced corrosion by removing hydrogen ions from metal cathodes; safety risks due to the production of hydrogen sulfide; and a decrease in polymer viscosity in polymer flooding oilfields, affecting the effectiveness of polymer flooding. The current effective method to mitigate the hazards of SRB is biological suppression through the introduction or activation of nitrate-reducing bacteria (NRB), leveraging inter-species competition. This paper conducted an on-site trial at a polymer flooding station in Shengli Oilfield, achieving satisfactory results.

Iron-based nanomaterials enhanced immobilization of Cd2+ and Pb2+ in mine wastewater and soil by Clostridium sulfidigenes HY-1.

Iron-based nanomaterials enhanced immobilization of Cd2+ and Pb2+ in mine wastewater and soil by Clostridium sulfidigenes HY-1.

Anaerobic Bioremediation of Acid Mine Drainage Using Sulphate-Reducing Bacteria: Current Status, Challenges, and Future Directions

Biological reduction of sulphates has gradually replaced unit chemical processes for the treatment of acid mine drainage (AMD), which exerts a significant environmental impact due to its elevated acidity and high concentrations of heavy metals. Bioremediation is optimally suited for the treatment of AMD because it is cost-effective and efficient. Anaerobic bioremediation employing sulphate-reducing bacteria (SRB) presents a promising solution by facilitating the reduction of sulphate to sulphide. The formed can precipitate and immobilise heavy metals, assisting them in their removal from contaminated wastewater. This paper examines the current status of SRB-based bioremediation, with an emphasis on recent advances in microbial processes, reactor design, and AMD treatment efficiencies. Reviewed studies showed that SRB-based bioreactors can achieve up to 93.97% of sulphate reduction, with metal recovery rates of 95% for nickel, 98% for iron and copper, and 99% for zinc under optimised conditions. Furthermore, bioreactors that used glycerol and ethanol as a carbon source improved the efficiency of sulphate reduction, achieving a pH neutralisation from 2.8 to 7.5 within 14 days of hydraulic retention time. Despite the promising results achieved so far, several challenges remain. These include the need for optimal environmental conditions, the management of toxic hydrogen sulphide production, and the economic feasibility of large-scale applications. Future directions are proposed to address these challenges, focusing on the genetic engineering of SRB, integration with other treatment technologies, and the development of cost-effective and sustainable bioremediation strategies. Ultimately, this review provides valuable information to improve the efficiency and scalability of SRB-based remediation methods, contributing to more sustainable mining practices and environmental conservation. To ensure relevance and credibility, relevance and regency were used as criteria for the literature search. The literature sourced is directly related to the subject of the review, and the latest research, typically from the last 5 to 10 years, was prioritised.

Cathodic protection and sulphate-reducing bacteria: a complex interaction in offshore steel structures

Abstract Microbiologically influenced corrosion (MIC) caused by sulphate-reducing bacteria (SRB) is an important issue, particularly in the offshore industry where cathodic protection (CP) is commonly used to prevent the corrosion of steel structures. However, its relation with MIC remains unclarified, as the interaction between CP and microbial activity is still far from understood. Under overprotection conditions, the water reduction reaction can lead to atomic hydrogen uptake, which may result in hydrogen embrittlement (HE). This uptake is influenced by calcareous deposits, i.e. inorganic compounds formed during CP. Additionally, SRB are argued in literature to enhance hydrogen uptake. This review explores various perspectives on the interaction between microbial activity, particularly SRB, and CP, as well as their individual and combined impact on hydrogen uptake in an offshore context.

Taxonomic diversity of microbial communities in the cold sulfur spring Bezymyanny (Pribaikalsky district, Republic of Buryatia)

The environmental conditions of cold sulfur springs favor the growth and development of abundant and diverse microbial communities with many unique sulfur cycle bacteria. In this work, the taxonomic diversity of microbial communities of three different biotopes (microbial mat, bottom sediment, and water) in the cold sulfur spring Bezymyanny located on the shore of Lake Baikal (Pribaikalsky district, Republic of Buryatia) was studied using highthroughput sequencing of the 16S rRNA gene. By sequencing the microbial mat, bottom sediment, and water samples, 76,972 sequences assigned to 1,714 ASVs (ASV, amplicon sequence variant) were obtained. Analysis of the ASV distribution by biotopes revealed a high percentage (66–93 %) of uniqueness in the three communities studied. An estimate of the alpha diversity index showed that bottom sediment community had higher indices, while microbial mat community was characterized by a lowest diversity. Bacteria of the phyla Pseudomonadota, Bacteroidota, Campylobacterota, Actinomycetota, Desulfobacterota dominated in different proportions in the studied communities. The features of the community structure of the studied biotopes were established. The microbial mat community was represented mainly by Thiothrix (43.2 %). The bottom sediment community was based on Sulfurovum (11.2 %) and co-dominated by unclassified taxa (3.2–1 %). Sequences assigned to the genera Novosphingobium, Nocardioides, Legionella, Brevundimonas, Sphingomonas, Bacillus, Mycobacterium, Sphingopyxis, Bradyrhizobium and Thiomicrorhabdus were found only in the water microbial community. Sulfur-oxidizing bacteria (SOB) and sulfate-reducing bacteria (SRB) were identified in all the communities studied, which indicates the ongoing processes of the sulfur cycle in the Bezymyanny spring ecosystem. It should be noted that sequences of unclassified and uncultivated sulfur cycle bacteria were present in all communities and a significant proportion of sequences (20.3–53.9 %) were not classified.

Silicon-iron modified biochar remediates cadmium and arsenic co-contaminated paddy soil by regulating cadmium and arsenic speciation

IntroductionSilicon–iron-modified biochars (SMBCs) were produced to remediate paddy soil contaminated with both cadmium (Cd) and arsenic (As). This study explored the effects of SMBCs on the transformation of Cd and As species in soil and the associated responses of functional genes to elucidate the remediation mechanisms.MethodThree silicon–iron modified biochars were utilized. (i) Silicon dioxide magnetic biochar (SMBC1), (ii) Calcium silicate magnetic biochar (SMBC2), and (iii) Sodium silicate magnetic biochar (SMBC3) were applied to paddy soil.Results and discussionSMBCs increased the soil pH and the concentration of dissolved organic carbon (DOC) by 0.42–0.54 units and 6.6–16.39%, respectively. SMBC treatments reduced the bioavailable concentrations of Cd and As by 29.09–73.63% and 1.67–8.37%, respectively, transforming As(III) into less toxic As(V) and stabilizing soluble Cd into a more inert residual form. Compared to the control, SMBC significantly increased residual Cd concentrations by 2.94–16.17% (p < 0.05) and As(V) concentrations by 11.42–26.07% (p < 0.05). Adding calcium silicate (CaSiO3) at a mass ratio of 5% to magnetic biochar resulted in a residual Cd concentration of 0.79 mg·kg−1 (an increase of 16.86%) and an As(V) concentration of 37.89 mg·kg−1. SMBCs enhanced soil porosity, microbial aioA genes, and sulfate-reducing bacteria, facilitating the oxidation of As(III). Magnetic biochar amended with 5% (CaSiO3) (SMBC2) demonstrated superior efficacy in addressing the co-contamination of Cd and As. The remediation mechanisms include the following: (i) an increase in soil pH and a decrease in dissolved organic carbon (DOC), (ii) enhanced aioA gene activity, promoting the oxidation of As(III) to As(V), and increased dissimilatory sulfite reductase beta subunit (DsrB) gene activity, facilitating the reduction of sulfate ion (SO42−) to sulfide ion (S2−), leading to the formation of cadmium sulfide (CdS) precipitates and additional precipitation involving As and Fe. These results highlight the potential of calcium silicate–modified magnetic biochar as an effective additive for Cd and As co-contaminated soils, providing insights into heavy metals’ stabilization and transformation mechanisms.

Baseline abundance of Akkermansia muciniphila and Bacteroides acidifaciens in a healthy state predicts inflammation associated tumorigenesis in the AOM/DSS mouse model

Numerous studies demonstrate that intestinal microbiota contribute to colorectal cancer (CRC), which is often associated with dysbiosis. Most of the data were obtained from studies on CRC patients, making it challenging to determine whether alterations in microbiota are a consequence of the pathology or whether they actively drive its progression. Several studies using laboratory animals suggest that gut microbiota may be involved in both the onset and progression of CRC. In the present study we utilized the azoxymethane-dextran sulfate sodium (AOM/DSS) mouse model of CRC to investigate the contribution of healthy-state microbiota to inflammation-associated tumorigenesis. Two cohorts of C57BL/6 mice harboring different intestinal microbiota demonstrated different susceptibility to AOM/DSS treatment. Sequencing of 16S rRNA bacterial DNA from fecal samples revealed Akkermansia muciniphila and Bacteroides acidifaciens as marker features in the healthy-state microbiota (before AOM/DSS administration), which showed a strong positive correlation with tumor incidence. Moreover, the healthy-state abundance of these markers, considered beneficial bacteria, was strongly positively correlated with the sulfate-reducing bacteria Desulfovibrio fairfieldensis identified as a marker of chronic colitis-associated microbiota. Furthermore, the abundances of these marker features, associated with CRC outcome, correlated with the expression of interferon gamma and nitric oxide synthase 2 genes in colon tissue during the early stage of DSS-induced intestinal inflammation. In contrast to multiple studies demonstrating the anti-inflammatory properties of A. muciniphila and B. acidifaciens, our results point out their potential adverse effect under specific conditions of genotoxicity and inflammation in the intestine. Taken together, our findings suggest a complex, context-dependent role of commensal microbiota in inflammation-associated dysbiosis and CRC.

Running against the clock: exploring microbial diversity in an extremely endangered microbial oasis in the Chihuahuan Desert.

The Cuatro Ciénegas Basin is a biodiversity hotspot known for its unique biodiversity. However, this ecosystem is facing severe anthropogenic threats that are drying its aquatic systems. We investigated microbial communities at three sites with different physicochemical and environmental characteristics (Pozas Rojas, Archean Domes, and the Churince system) within the basin to explore potential connections to deep aquifers and determine if the sites shared microorganisms. Utilizing 16S rRNA gene data, we identified a core microbiota between Pozas Rojas (PR) and Archean Domes (AD). Sulfur reduction appears to shape the microbial connectivity among sites, since sulfur-reducing bacteria has the highest prevalence between samples from PR and AD: Halanaerobium sp. (88.46%) and Desulfovermiculus halophilus (65%); and between the Churince system and AD: Halanaerobium sp. (63%) and D. halophilus (60%). Furthermore, metagenome-assembled genomes from Ectothiorhodospira genus were found in both AD and Churince, suggesting microbial dispersal. An important finding is that microbial diversity in the AD system declined, from 2016 to 2023 the ecosystem lost 29 microbial phyla. If this trend continues, the basin will lose most of its water, resulting in the loss of various prokaryotic lineages and potential biotechnological solutions, such as enzymes or novel antibiotics. Our findings highlighting the need for water extraction regulations to preserve the basin's biodiversity.

Polymer biodegradation by Halanaerobium promotes reservoir souring during hydraulic fracturing.

Hydraulically fractured shale oil reservoirs are ideal for studying extremophiles such as thermohalophiles. During hydraulic fracturing, reservoir production water is stored in surface ponds prior to reuse. Microorganisms in these systems therefore need to withstand various environmental changes such as the swing between warm downhole oil reservoir temperatures and cooler surface conditions. While most studies on hydraulically fractured oil reservoirs mimic the environmental conditions found in oil wells, this study follows this water cycle during fracking and the associated microbial metabolic potential during topside-produced water storage and subsurface oil reservoir conditions. Of particular interest are members of the genus Halanaerobium that have been reported to reduce thiosulfate contributing to souring of oil reservoirs. Here, we show that some Halanaerobium strains were unable to grow at hotter temperatures reflective of oil reservoir conditions and lack genes for thiosulfate reduction, despite the proposed importance of this metabolism in other studies. Rather, it is likely that these organisms metabolize complex organics in fracking fluids at lower temperatures, thereby generating substrates that support reservoir souring by thermophilic sulfate-reducing bacteria at higher temperatures. In this way, Halanaerobium promotes souring indirectly by feeding sulfate-reducing microorganisms fermentation products (e.g., acetate and hydrogen) rather than via direct sulfidogenesis via thiosulfate reduction. Therefore, the novelty of this research is not within the detection of known oil reservoir colonizing bacteria but rather in the relationship between bacteria and the indirect involvement of Halanaerobium, promoting souring throughout the produced water reuse cycle.

Dual role of microorganisms in metal corrosion: a review of mechanisms of corrosion promotion and inhibition

The dual role of microorganisms in metal corrosion and corrosion inhibition reflects their complex biochemical interactions. In terms of corrosion, certain microorganisms accelerate metal oxidation by producing acidic metabolites or facilitating electrochemical processes, thereby causing damage to the material. Conversely, under specific conditions, they can form biofilms and/or biominerals that create protective layers, reducing the oxidation rate and delaying corrosion. This paper provides a comprehensive illustration of microbial corrosion promotion and inhibition, emphasizing the importance of key microorganisms involved in these corrosive processes. Microorganisms, including sulfate-reducing bacteria, nitrate-reducing bacteria, iron-oxidizing and iron-reducing bacteria and certain fungi, contribute to corrosion through their metabolic activities. Microbial corrosion mechanisms can be classified into extracellular electron transfer, microbial metabolism corrosion and the oxygen concentration cell theory. In contrast, microorganisms can effectively mitigate metal corrosion through a range of mechanisms including reduction of dissolved oxygen levels, secretion of antimicrobial substances, biological competition and biomineralization. Microbial corrosion and inhibition generally arise from multiple mechanisms working together, rather than a single cause. A deeper understanding of these mechanisms can provide a theoretical basis and practical guidance for the development of new anti-corrosion strategies.

Adsorption characteristics of sulfate reducing bacteria Clostridium sp. on lignite surface.

Biogenic coal bed methane has attracted great attention in recent years. During the process of biogas production, the interaction between microorganisms and coal is a crucial step. Sulfate-reducing bacteria (SRB) play an important role in biogas production. However, the interaction between SRB and coal has always remained an open problem. In the present work, the SRB strain Clostridium sp. and lignite were used to investigate the adsorption process with the extended DLVO (XDLVO) theory, calorimetry, and scanning electron microscopy (SEM). The results showed that the adsorption rate has a positive correlation with pH when it went from 3 to 8. XDLVO theoretical analysis was in good agreement with the adsorption experimental result. Acid-base potential energy is a more critical factor driving the adsorption comparing with electrostatic potential energy and Lifshitz-van Der Waals potential energy. The adsorption process of Clostridium sp. cells on lignite surface can be divided into three main stages: the direct adsorption, or reversible adsorption; desorption process; and irreversible adsorption. From the SEM results, the intercellular cohesion is also a very important adsorption form. The morphology and roughness of coal surface may also have a key effect on adsorption. Overall, our results provide some insights into the surface energy changes of Clostridium sp. adsorbed on coal and their interactions from the perspective of adsorption kinetics.

Growth on Hydrogen by the Sulfate-Reducing Oleidesulfovibrio alaskensis Induces Biofilm Dispersion and Detachment─Implications for Underground Hydrogen Storage.

Hydrogen is a versatile energy carrier for human activity but is also a ubiquitous electron donor for subsurface microorganisms. During underground hydrogen storage operations, it is expected that microbial communities will use the injected hydrogen as electron donor for diverse metabolisms, and induce a variety of microbial-triggered risks. A significant concern is the formation of biofilm and induced bioclogging, which may reduce the hydrogen injectivity and storage operation efficiency by altering the subsurface hydrogen flow. This study investigates how different electron donors─specifically hydrogen and lactate─affect the growth dynamics of a sulfate-reducing bacterium (Oleidesulfovibrio alaskensis G20) and the associated biofilm formation in porous media. The pore-scale observations reveal that lactate promotes robust biofilms resulting in bioclogging, compared to hydrogen promoting increased microbial motility with less biomass production. Potential hydrogen chemotaxis leads to biofilm dispersal and detachment over time as the cells seemingly favor a planktonic lifestyle over biofilm formation. Multiple hydrogen injections enhanced biofilm detachment and reduced the risk of pore blockage associated with microbial growth. Three hydrogen injections resulted in 69% biofilm detachment, while nitrogen injection caused only 31% detachment over three cycles. The combination of increased cell motility and reduced biofilm attachment indicates that the risk of bioclogging during cyclic UHS operation might be low for this model bacterial strain.

Distinguishing the Contribution of Extracellular Electron Transfer in the Desulfovibrio caledoniensis-Induced Total Corrosion of Q235 Carbon Steel

Microbially influenced corrosion (MIC) in anaerobic environments accounts for many severe failures and losses in different industries. Sulfate-reducing bacteria (SRB) represent a typical class of corrosive microorganisms capable of acquiring electrons from steel through extracellular electron transfer processes, thereby inducing severe electrical microbially influenced corrosion (EMIC). Although prior research has underscored the significance of extracellular electron transfer, the contribution of EMIC to the whole MIC has not been comprehensively studied. In this study, Q235 steel coupons were employed in an H-shaped electrochemical cell to conduct electrochemical and coupon immersion experiments, aiming to determine the contribution of EMIC to the overall MIC. The experiments were conducted under two distinct carbon source conditions: 100% carbon source (CS) and 1% CS environments. It was observed that the biotic electrodes exhibited significantly higher cathodic currents, with the most pronounced biological cathodic activity detected in the 100% CS biotic medium. The voltammetric responses of the electrodes before and after changes in the medium confirmed the biocatalytic capability of the attached biofilm in stimulating the cathodic reaction. The proportion of EMIC in MIC was calculated using linear polarization resistance, revealing a trend over time. Additionally, weight loss tests indicated that the contribution of EMIC to the total MIC was approximately 27.69%. Furthermore, the results demonstrated that while the overall corrosion rate was lower in the 1% CS environment, the proportion of EMIC in MIC increased to approximately 37.68%.

Investigation of Suitable, Readily Available, Sources of Sulfate-Reducing Bacteria Inoculum, and Evaluation of Sulfate Reduction Rates Achieved at Different pHs.

This study investigated the suitability of readily available and naturally occurring sources of microorganisms (inoculum) to use for the cultivation of sulphate-reducing bacteria (SRB) for acid mine drainage (AMD) remediation. The selected inocula included AMD water (AMD), mud (MUD) and reed-bed mud (RM) from the AMD surrounds, mealworms (MW), cow dung (CD) and raw sewage sludge (RS). The suitability of the different inoculum sources was evaluated by comparing the SO4 2- reduction and sulfide (S2-) production rates at three different pHs. Experimental results showed that the AMD, MW, MUD and CD inoculum did not produce appreciable reduction of SO4 2- to S2- and were unsuitable sources of SRB inoculum. The inoculum evaluated in pH 2 media did not achieve SO4 2- reduction. Of the inoculum assessed in pH 4 media, only the RM inoculum achieved SO4 2- reduction (40%) with S2- production (36 mg/L). In contrast, a notable S2- production, RS (114 mg/L) and RM (99 mg/L), accompanied the SO4 2- reduction achieved in the pH 7.5 RS (44%) and RM (30%) samples. The improved S2- produced/SO4 2- removed conversion ratios for samples pH 7.5 RS (0.14) and pH 7.5 RM (0.17) are indicative of increased SRB activity and the suitability of these inoculum as SRB sources.

Nanozyme-based dual-mode DNA biosensor for self-powered ultrasensitive detection of sulfate-reducing bacteria.

Nanozyme-based dual-mode DNA biosensor for self-powered ultrasensitive detection of sulfate-reducing bacteria.

Cobalt regulation biocathode with sulfate-reducing bacteria for enhancing the reduction of antimony and the removal of sulfate in a microbial electrolysis cell simultaneously.

Cobalt regulation biocathode with sulfate-reducing bacteria for enhancing the reduction of antimony and the removal of sulfate in a microbial electrolysis cell simultaneously.

Intelligent antibacterial coatings based on sensitive response and periodic fast drug release for long-term defense against corrosion induced by sulfate-reducing bacteria.

Intelligent antibacterial coatings based on sensitive response and periodic fast drug release for long-term defense against corrosion induced by sulfate-reducing bacteria.

Reliable and accessible point-of-use water denitrification system

This paper describes the design and operation of a reliable and accessible point-of-use water denitrification system. The system includes a U-shaped submersible denitrifying biofilter and a bubble-film extractor. The biofilter utilizes the combined actions of denitrifying, sulfate-reducing, and sulfur bacteria. Denitrifying bacteria convert nitrates into nitrogen gas and reduce the calcium hardness of water in proportion to the nitrate concentration. When the water is contaminated with both nitrates and sulfates and the bacterial community receives excess nutrients (ethanol), some sulfates are converted into hydrogen sulfide. This process facilitates the removal of heavy metal ions from the water in the form of hydrosulfides. When the sulfate-reducing bacteria produce excess hydrogen sulfide, the sulfur bacteria convert it into colloidal sulfur at the biofilter outlet. The bubble-film extractor removes colloidal sulfur, heavy metal hydrosulfides, calcium carbonate dispersions, and hydrogen sulfide from the filtrate. The system is user-friendly, requiring no special skills or knowledge for installation and maintenance. The proposed system demonstrates cost-effective denitrification and water polishing over long-term use.

Sulfate-reducing bacteria in removal of pollutants: a promising candidate for bioremediation

Sulfate-reducing bacteria in removal of pollutants: a promising candidate for bioremediation