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ABSTRACT This study aim is to elucidate the relationship between the microbial community dynamics and the production of volatile flavor compounds during the fermentation process of bacterial‐type Douchi. Using high‐throughput sequencing (HTS) and headspace solid‐phase microextraction, gas chromatography–mass spectrometry (HS‐SPME‐GC–MS) was used to investigate microbial diversity and volatile compound profiles at different fermentation stages. Spearman correlation analysis was employed to identify potential associations between microbial genera and flavor compounds. The results revealed that the dominant bacterial phyla were Pseudomonadota and Firmicutes, with the dominant genera being Bacillus, Enterobacter, and Weissella. The dominant fungal phyla were Ascomycetes and Mucoromycota, whereas the dominant genera were Aspergillus, Trastula, and Pythium. A total of 110 volatile substances (relative to a relative content ≥ 0.03%) were detected during the fermentation process of bacterial‐type Douchi. These included 34 hydrocarbons, 17 alcohols, 11 heterocyclic compound, 10 acids, 9 ketones, 9 esters, 6 aldehydes, 6 sulfur compounds, and 8 other compounds. The characteristic flavor compounds identified were ethanolamine, 2,3‐butanediol, benzoaldehyde, 3‐hydroxy‐2‐butanone, pterin‐6‐carboxylic acid, ethyl heptanoate, and diallyl disulfide. Correlation analysis indicated a strong positive association between benzoin aldehyde and pterin‐6‐carboxylic acid with the genera Thiobacillus and Pythium. Ethyl heptanoate was positively correlated with Enterobacter, Weissella, and Trasmium. Additionally, 3‐hydroxy‐2‐butanone was positively correlated with the genus Staphylococcus. This research provides valuable insights into the microbial and chemical dynamics of bacterial‐type Douchi fermentation, offering guidance for optimizing fermentation processes to improve product quality. [ABSTRACT FROM AUTHOR]

Microorganism-based ecotoxicity assessment has been widely used as a reliable tool showing direct biochemical impacts of contaminants on ecosystems and the environment. The present study aimed at developing a thiosulfate-utilizing denitrifying bacteria (TUDB)-based ecotoxicity test with high detection sensitivity and favorable reproducibility. To achieve this goal, existing TUDB toxicity tests were improved by employing a pure culture of Thiobacillus thioparus ATCC 8158 and optimizing test conditions, particularly in terms of inoculated microbial biomass, incubating temperature, and operational pH. From control tests, it was found that 4 h is a sufficient processing time for TUDB test kits. As a result of optimization, 20 mg VSS/L of initial bacterial biomass, 25 °C of incubating temperature, and 6 of operational pH were determined as the most favorable test conditions, providing enhanced detection sensitivity and reproducibility. Under these optimal test conditions, I conducted toxicity tests for diverse toxic metals and obtained 0.65 ± 0.03, 1.09 ± 0.04, 1.21 ± 0.07, 0.13 ± 0.01, 0.56 ± 0.04, 1.42 ± 0.03, 0.98 ± 0.02, and 2.12 ± 0.05 mg/L of 4 h EC50 values for Ag+, As3+, Cd2+, Cr6+, Cu2+, Hg2+, Ni2+, and Pb2+, respectively. These EC50 values are substantially lower than those from earlier TUDB tests, demonstrating the high detection sensitivity of the current TUDB tests. Moreover, the present TUDB tests attained very low coefficient of variation (CV) values (1.6–6.3%) for the EC50, showing favorable reproducibility of the test methodology. In addition, the current TUDB toxicity tests offer numerous advantages for ecotoxicity assessment, including versatility for diverse test samples, no requirement for advanced equipment, and no distortion of end-point measurement. These refinements render the TUDB tests a favorable ecotoxicity assessment with enhanced sensitivity and reproducibility. [ABSTRACT FROM AUTHOR]

To provide the necessary nitrite for the Anaerobic Ammonium Oxidation (ANAMMOX) process, the effect of nitrite accumulation in the partial sulfide autotrophic denitrification (PSAD) process was investigated using an SBR reactor. The results revealed that the effectiveness of nitrate removal was unsatisfactory when the S/N ratio (mol/mol) fell below 0.6. The optimal conditions for nitrate removal and nitrite accumulation were achieved within the S/N ratio range of 0.7-0.8, resulting in an average Nitrate Removal Efficiency (NRE) of 95.84%±4.89% and a Nitrite Accumulation Rate (NAR) of 75.31%±6.61%, respectively. It was observed that the nitrate reduction rate was three times faster than that of nitrite reduction during a typical cycle test. Furthermore, batch tests were conducted to assess the influence of pH and temperature conditions. In the pH tests, it became evident that the PSAD process performed more effectively in alkaline environment. The highest levels of nitrate removal and nitrite accumulation were achieved at an initial pH of 8.5, resulting in a NRE of 98.30%±1.93% and a NAR of 85.83%±0.47%, respectively. In the temperature tests, the most favourable outcomes for nitrate removal and nitrite accumulation were observed at 22±1 ℃, with a NRE of 100.00% and a NAR of 81.03%±1.64%, respectively. Moreover, a comparative analysis of 16S rRNA sequencing results between the raw sludge and the sulfide-enriched culture sludge sample showed that Proteobacteria (49.51%) remained the dominant phylum, with Thiobacillus (24.72%), Prosthecobacter (2.55%), Brevundimonas (2.31%) and Ignavibacterium (2.04%) emerging as the dominant genera, assuming the good nitrogen performance of the system. [ABSTRACT FROM AUTHOR]

Thiocyanate (SCN−) exists in various industries and is detrimental to the ecosystem, necessitating cost-effective and environmentally benign treatment. In response to alleviate the bacterial toxicity of SCN−, this study developed a two-stage coupled system by tandem of anammox in reactor 1 (R1) and SCN−-driven autotrophic denitrification in reactor 2 (R2), achieving simultaneous removal of SCN− and nitrogen. The total nitrogen removal efficiency of the coupled system was 92.42 ± 1.98%, with nearly 100% of SCN− elimination. Thiobacillus was responsible for SCN− degradation. The deduced degradation pathway of SCN− was via the cyanate pathway before coupling, followed by the co-action of cyanate pathway and carbonyl sulfide pathway after coupling. Although scaling-up study is needed to validate its applicability in real-world applications, this study contributes to the advancement of sustainable and cost-effective wastewater treatment technologies, being an attractive path for low-carbon nitrogen removal and greenhouse gas emission-free technology. [ABSTRACT FROM AUTHOR]

The effects of autumn sowing and chemical, organic, and biological fertilizer sources were explored on yield components and physiological traits of dragon’s head (Lallemantia iberica Fisch. & C.A.Mey). The study was conducted as a factorial experiment based on a randomized complete block design with three replications in a field experiment in the 2017-2018 crop year. The fertilizer treatments included organic fertilizers (vermicompost, manure, and humic acid), biofertilizer (Thiobacillus mixed with sulfur), chemical fertilizer (macro NPK), and control (no fertilizer). The studied traits included seed yield per ha, harvest index, biological yield per ha, chlorophyll a, chlorophyll b, carotenoid, proline, and dissolved carbohydrate. The results of the comparison of the means revealed that the winter sowing outperformed the spring sowing evidently and increased traits like seed yield per ha, biological yield per ha, and harvest index significantly. The fertilization of the plants in both sowing seasons, especially in the winter sowing, increased seed yield per ha, biological yield per ha, and harvest index so that the vermicompost-fertilized winter-sown plants produced the highest seed yield per ha (0.91 g), whereas the application of manure was related to the highest harvest index in the winter sowing (27.9%). The highest biological yield (8797 kg ha-1 ) was related to the treatment of Thiobacillus of the winter-sown plants. Proline content was higher in the spring sowing plants, and the control treatment in the spring sowing had the highest proline content (0.120 mg g-1 ). Concerning dissolved carbohydrates, the spring sowing and the unfertilized plants had the highest content (20.3 mg g-1 ). On the other hand, chlorophyll a, chlorophyll b, and carotenoid were higher in the treatments of Thiobacillus and vermicompost, which resulted in achieving higher yields due to the increase in photosynthesis rate. According to the results, the winter sowing of the dragon’s head in the Azerbaijan region of Iran and the use of Thiobacillus and vermicompost could be recommended for obtaining plants with optimum quality parameters. [ABSTRACT FROM AUTHOR]

A novel coupling process to replace the traditional multi-stage anammox process—sulfur autotrophic denitrification (SAD) coupled anaerobic ammonium oxidation (anammox) system was designed, which solved problems of nitrate produced in anammox process and low nitrate conversion rate caused by nitrite accumulation in SAD process. Different filter structures (SAD filter and anammox granular sludge) were investigated to further explore the excellent performance of the novel integrated reactor. The results of sequential batch experiments indicated that nitrite accumulation occurred during SAD, which inhibited the conversion of nitrate to dinitrogen gas. When SAD filter and anammox granular sludge were added to packed bed reactor simultaneously, the nitrate removal rate increased by 37.21% and effluent nitrite concentration decreased by 100% compared to that achieved using SAD. The stratified filter structure solved groove flow. Different proportion influence of SAD filter and anammox granular sludge on the stratified filter structure was evaluated. More suitable ratio of SAD filter to anammox granular sludge was 2:1. Proteobacteria (57.26%), Bacteroidetes (20.12%) and Chloroflexi (9.95%) were the main phyla. The dominant genera of denitrification functional bacteria were Thiobacillus (39.80%), Chlorobaculum (3.99%), norank_f_PHOs-HE36 (2.90%) and Ignavibacterium (2.64%). The dominant genus of anammox bacterium was Candidatus_Kuenenia (3.05%). [ABSTRACT FROM AUTHOR]

The climate change and consequent degradation of soil and water resources have led to difficult conditions for farmers; thus, they should make intelligent decisions to face these statuses. Managing soil nutrient and mineral uptake by plants and its feasibility under harsh environment must be considered. Therefore, the present research was conducted to investigate the response of pomegranate variety Shishe Kab to Thiobacillus bacteria (B) and sulfur (S) fertilization. Treatments included sulfur fertilization (three levels: 0, 500 and 1000 g−1 tree) and inoculation with Thiobacillus bacteria (two levels: inoculated and non-inoculated). Totally, sulfur fertilization and inoculation with bacteria improved physiological and biochemical aspects and fruit production of pomegranate. Supplying S decreased soil pH, which the lowest value (5.2) was recorded in 500 g S tree−1 when accompanied with bacteria. Soil electrolyte leakage (EL) increased, when sulfur incorporated or when bacteria added to the soil. The interactive effects of B × S was significant on fruit diameter and weight, chlorophyll (Chl), carotenoid and potassium content, which were improved, although non-inoculated plants also showed high values of potassium content. Anthocyanin and total carbohydrate improved when bacteria inoculation was done; however, total acidity (TA) and total soluble solids (TSS) showed a significant decrease. The EL variable significantly decreased and tissue water content increased in this experiment, when inoculation or sulfur fertilization was used. The results obtained from present study emphasized on the necessity of using sulfur and Thiobacillus bacteria in increasing growth and yield and also chilling tolerance of pomegranate trees. From the experiment we found that supplying sulfur alone or accompanied with Thiobacillus bacteria gave the amazing results, lead to increase plant growth and development, yield increase and biochemical changes that are helpful under harsh environmental conditions, specifically cold and freezing stresses. [ABSTRACT FROM AUTHOR]

The nitrate removal efficiency of a 9.5 L packed bed column bioreactor was evaluated using different feeding strategies and initial concentrations. The bioreactor was filled with zeolite mineral particles and initially treated with Thiobacillus denitrificans. Several hydraulic retention times were examined to assess the effectiveness of nitrate removal. The most favorable scenario resulted in an 87% reduction in nitrate concentration from an influent of 400 mg/L within a three-hour period. To determine the optimal length of the bioreactor, a computational fluid dynamics model was developed. By comparing simulations with experimental results, the ideal height of the bioreactor for complete denitrification was determined to be 90 cm, 45 cm, 30 cm, and 20 cm for influents with nitrate concentrations of 400 mg/L, 250 mg/L, 120 mg/L, and 80 mg/L, respectively. [ABSTRACT FROM AUTHOR]

Pulp-paper mills (PPMs) are known for consistently generating a wide variety of pollutants, that are often unidentified and highly resistant to environmental degradation. The current study aims to investigate the changes in the indigenous bacterial communities profile grown in the sediment co-contaminated with organic and inorganic pollutants discharged from the PPMs. The two sediment samples, designated PPS-1 and PPS-2, were collected from two different sites. Physico-chemical characterization of PPS-1 and PPS-2 revealed the presence of heavy metals (mg kg-1) like Cu (0.009-0.01), Ni (0.005-0.002), Mn (0.078-0.056), Cr (0.015-0.009), Pb (0.008-0.006), Zn (0.225-0.086), Fe (2.124-0.764), Al (3.477-22.277), and Ti (99.792-45.012) along with high content of chlorophenol, and lignin. The comparative analysis of organic pollutants in sediment samples using gas chromatography-mass spectrometry (GC-MS) revealed the presence of major highly refractory compounds, such as stigmasterol, β-sitosterol, hexadecanoic acid, octadecanoic acid; 2,4-di-tert-butylphenol; heptacosane; dimethyl phthalate; hexachlorobenzene; 1-decanol, 2-hexyl; furane 2,5-dimethyl, etc in sediment samples which are reported as a potential toxic compounds. Simultaneously, high-throughput sequencing targeting the V3-V4 hypervariable region of the 16S rRNA genes, resulted in the identification of 1,249 and 1,345 operational taxonomic units (OTUs) derived from a total of 115,665 and 119,386 sequences read, in PPS-1 and PPS-2, respectively. Analysis of rarefaction curves indicated a diversity in OTU abundance between PPS-1 (1,249 OTUs) and PPS-2 (1,345 OTUs). Furthermore, taxonomic assignment of metagenomics sequence data showed that Proteobacteria (55.40%; 56.30%), Bacteoidetes (11.30%; 12.20%), and Planctomycetes (5.40%; 4.70%) were the most abundant phyla; Alphproteobacteria (20.50%; 23.50%), Betaproteobacteria (16.00%; 12.30%), and Gammaproteobacteria were the most recorded classes in PPS-1 and PPS-2, respectively. At the genus level, Thiobacillus (7.60%; 4.50%) was the most abundant genera grown in sediment samples. The results indicate significant differences in both the diversity and relative abundance of taxa in the bacterial communities associated with PPS-2 when compared to PPS-1. This study unveils key insights into contaminant characteristics and shifts in bacterial communities within contaminated environments. It highlights the potential for developing efficient bioremediation techniques to restore ecological balance in pulp-paper mill waste-polluted areas, stressing the importance of identifying a significant percentage of unclassified genera and species to explore novel genes. [ABSTRACT FROM AUTHOR]

Pulp-paper mills (PPMs) are known for consistently generating a wide variety of pollutants, that are often unidentified and highly resistant to environmental degradation. The current study aims to investigate the changes in the indigenous bacterial communities profile grown in the sediment co-contaminated with organic and inorganic pollutants discharged from the PPMs. The two sediment samples, designated PPS-1 and PPS-2, were collected from two different sites. Physico-chemical characterization of PPS-1 and PPS-2 revealed the presence of heavy metals (mg kg−1) like Cu (0.009–0.01), Ni (0.005–0.002), Mn (0.078–0.056), Cr (0.015–0.009), Pb (0.008–0.006), Zn (0.225–0.086), Fe (2.124–0.764), Al (3.477–22.277), and Ti (99.792–45.012) along with high content of chlorophenol, and lignin. The comparative analysis of organic pollutants in sediment samples using gas chromatography–mass spectrometry (GC–MS) revealed the presence of major highly refractory compounds, such as stigmasterol, β-sitosterol, hexadecanoic acid, octadecanoic acid; 2,4-di-tert-butylphenol; heptacosane; dimethyl phthalate; hexachlorobenzene; 1-decanol,2-hexyl; furane 2,5-dimethyl, etc in sediment samples which are reported as a potential toxic compounds. Simultaneously, high-throughput sequencing targeting the V3–V4 hypervariable region of the 16S rRNA genes, resulted in the identification of 1,249 and 1,345 operational taxonomic units (OTUs) derived from a total of 115,665 and 119,386 sequences read, in PPS-1 and PPS-2, respectively. Analysis of rarefaction curves indicated a diversity in OTU abundance between PPS-1 (1,249 OTUs) and PPS-2 (1,345 OTUs). Furthermore, taxonomic assignment of metagenomics sequence data showed that Proteobacteria (55.40%; 56.30%), Bacteoidetes (11.30%; 12.20%), and Planctomycetes (5.40%; 4.70%) were the most abundant phyla; Alphproteobacteria (20.50%; 23.50%), Betaproteobacteria (16.00%; 12.30%), and Gammaproteobacteria were the most recorded classes in PPS-1 and PPS-2, respectively. At the genus level, Thiobacillus (7.60%; 4.50%) was the most abundant genera grown in sediment samples. The results indicate significant differences in both the diversity and relative abundance of taxa in the bacterial communities associated with PPS-2 when compared to PPS-1. This study unveils key insights into contaminant characteristics and shifts in bacterial communities within contaminated environments. It highlights the potential for developing efficient bioremediation techniques to restore ecological balance in pulp-paper mill waste-polluted areas, stressing the importance of identifying a significant percentage of unclassified genera and species to explore novel genes.

In this study, we investigated the effects of salinity on elemental sulfur-driven autotrophic denitrification (SAD) efficiency, and microbial communities. The results revealed that when the salinity was≤6 g/L, the nitrate removal efficiency in SAD increased with the increasing salinity reaching 95.53% at 6 g/L salinity. Above this salt concentration, the performance of SAD gradually decreased, and the nitrate removal efficiency decreased to 33.63% at 25 g/L salinity. Approximately 5mg/L of the hazardous nitrite was detectable at 15 g/L salinity, but decreased at 25 g/L salinity, accompanied by the generation of ammonium. When the salinity was ≥15 g/L, the abundance of the salt-tolerant microorganisms, Thiobacillus and Sulfurimonas, increased, while that of other microbial species decreased. This study provides support for the practical application of elemental sulfur-driven autotrophic denitrification in saline nitrate wastewater. [ABSTRACT FROM AUTHOR]

Purpose: This study was to investigate the regulation of sulfur status in continuous-cropping soybean soil by Funneliformis mosseae and Thiobacillus thioparus and promote the absorption of sulfur in soybean. To explore the interactions among F. mosseae, T. thioparus and soybean plants, this study laid a theoretical foundation for the application of F. mosseae and T. thioparus as biological agents in agricultural production. Methods: Pot culture, a two-compartment system and shake-flask culture were used in the experiment. Using F. mosseae and T. thioparus as experimental inoculants, the effects of F. mosseae on sulfur oxide of T. thioparus and their interaction on the growth of soybean plants were studied from the aspects of soil sulfur content, sulfur functional genes and the growth of soybean and sulfur-oxidizing bacteria. Results: The F. mosseae and T. thioparus inoculation significantly increased the abundance of sulfur-oxidizing bacteria and available sulfur content in the soil, stimulated the expression of sulfate transporter genes in soybean roots, and promoted the absorption of sulfur nutrients in soybean. F. mosseae stimulated the expression of the T. thioparus sulfur-oxidation gene and enhanced the sulfur-oxidation capacity, while T. thioparus enhanced F. mosseae colonization of soybean roots. Thus, F. mosseae and T. thioparus promoted soil sulfur cycling and sulfate transport in soybean roots, which proved that F. mosseae could effectively improve the sulfur-oxidation capacity of T. thioparus. Conclusion: Double inoculation with F. mosseae and T. thioparus significantly promoted soybean plant growth and increased soil sulfur utilization. [ABSTRACT FROM AUTHOR]

Sulfur (S) deficiency is becoming more common in agro-ecosystems worldwide due to factors such as agronomic practices, high biomass production, reduced sulfur emissions, and the use of non-sulfur fertilizers. This review explores the natural occurrence and commercial exploitation of sulfur pools in nature, the mineralization and immobilization of sulfur, the physiological role of sulfur in plants, and its deficiency symptoms. Additionally, the organic and inorganic forms of sulfur in soil, their transformations, and the process of microbiological oxidation of sulfur are discussed. The review also addresses the diversity of sulfur-oxidizing bacteria (SOB) and the various biochemical mechanisms involved in their role in plant productivity and soil reclamation. The measurement of S oxidation rate in soil and the variables that influence the process are also examined. Typically, the rate of oxidation of added elemental S is around 40%–51%, which is available for plant uptake. These characteristics of SOB demonstrate their potential as bioinoculants for increasing plant growth, indicating their use as biofertilizers for sustainable crop production in agro-ecosystems. [ABSTRACT FROM AUTHOR]

Anaerobic digestion produces biogas which usually contains 60-70% of methane (CH4), 30-40%of carbon-di-oxide (CO2), and 10-2,000 ppm hydrogen sulfide (H2S). The concentration of H2S depends upon the type of substrate. H2S tends to corrode pipes and machines carrying them. The high concentrations of H2S present in biogas may adversely affect electricity generation. Hence, the removal of H2S and enrichment of biogas with CH4 is an essential step towards higher energy production. In the present study, the biological method of removing H2S using Thiobacillus sp. was demonstrated for a one cu.m anaerobic co-digestion (ACD) unit running on an organic fraction of municipal solid waste (OFMSW) and septage sludge. Initial lab scale studies were conducted by collecting the biogas generated from 1 cu.m digesters, and continuous experiments were optimized for the process parameters such as flow rate, the volume of medium with culture, time, the height of the column, column composition, etc. The raw biogas was purged in a liquid medium (LM) with a culture containing Thiobacillus sp. The studies with the LM containing Thiobacillus sp. cultureshowed a 68% removal of H2S in the first 8 min, and the saturation occurred at 75 min when the time-dependent experiment was studied. The smaller flow rate (0.48 L.min-1) and highest volume of culture (500 mL) showed better results than other parameters. The highest and average oxidation rates of sulfate were recorded as 39 and 40.3 ppm.sec-1, respectively, for 0.48 L.min-1 flow rate and 500 mL of the culture volume. In the column studies, a column containing cocopeat (CP) was studied for its efficiency in removing H2S. At a flow rate of 0.9 L.min-1, 25% adsorption was encountered and reached saturation at 90 min. The bed height of 9 inches with CP and plastic support (PS) showed a 20% H2S removal. The filling ratio of CP and PS (1:1) was the best ratio for proper gas passage with optimal time for adsorption/absorption. The kinetic, isotherm, and continuous models helped to understand the capacity of the adsorbent. Freundlich, Yoon-Nelson, and BDST model were best fit for the present study. A pilot scale setup for one cu.m biogas reactor showed an average of 50% removal of H2S for LM with culture, and an additional 20% removal was possible by the introduction of a column along with the liquid bed in series. An overall efficiency of 70-75% of H2S removal was achieved. No significant CH4 loss was encountered during the study. [ABSTRACT FROM AUTHOR]

The ultimate purpose of phytoextraction is not only to remove heavy metals from soil but also to improve soil quality. Here, we evaluated how the joint effect of Streptomyces pactum (strain Act12) and inorganic (Hoagland's solution) and organic (humic acid and peat) nutrients affected the phytoextraction practice of cadmium (Cd) and zinc (Zn) by potherb mustard, and the microbial community composition within rhizosphere was also investigated. The results indicated that the nutrients exerted synergistically with Act12, all increasing the plant biomass and Cd/Zn uptakes. The inoculation of Act12 alone significantly increased dehydrogenase activity of rhizosphere soil (P < 0.05), while urease and alkaline phosphatase activities varied in different dosage of Act12. Combined application of microbial strain with nutrients increased enzymatic activities with the elevated dosage of Act12. 16S ribosomal RNA high-throughput sequencing analysis revealed that Act12 inoculation reduced the diversity of rhizosphere bacteria. The Act12 and nutrients did not change dominant phyla i.e. , Proteobacteria, Bacteroidetes, Gemmatimonadetes, Actinobacteria and Acidobacteria, but their relative abundance differed among the treatments with: Peat > Act12 > Humic acid > Hoagland's solution. Comparatively, Sphingomonas replaced Thiobacillus as dominant genus after Act12 application. The increase in the Sphingomonas and Flavisolibacter abundances under Act12 and nutrients treatments gave rise to growth-promoting effect on plant. Our results revealed the important role for rhizosphere microbiota in mediating soil biochemical traits and plant growth, and our approach charted a path toward the development of Act12 combined with soil nutrients to enhance soil quality and phytoextraction efficiency in Cd/Zn-contaminated soils. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Two-point inlet and internal recirculation reduced ∼50 % sulfate generation. • There were no sulfide emissions from S0-based bioreactor with dual layers. • Chlorobiaceae sp. exhibited predominantly positive association with other species. • Denitrification and sulfate reduction genes were more abundant in WSMDR than SADR. In this study, an elemental sulfur (S0) autotrophic denitrification reactor (SADR) and a wood chunk and S0 mixotrophic denitrification reactor (WSMDR) were constructed with dual-layers to effectively remove nitrate from water using two-inlets and internal recirculation. The denitrification rates were 66–114 and 70–104 g-N/(m3·d) for the SADR and WSMDR, respectively. Sulfate production was 5.5–5.9 and 3.2–4.5 mg SO 4 2−/mg reduced N in the SADR and WSMDR, respectively, being lower than theoretical value. In addition, there was no sulfide emission from either reactor. Chlorobium , Chlorobaculum , Ignavibacterium , Sulfuritalea , and Thiobacillus were involved in nitrate reduction in both reactors. Chlorobiaceae had the highest abundance and played an essential role in maintaining the integrity of the co-occurrence pattern. The abundance of functional genes positively correlated with the denitrification performance. This study demonstrates that the operation of two-inlets and internal recirculation can effectively reduce byproduct generation, thereby promoting the practical application of the SADR and WSMDR. [ABSTRACT FROM AUTHOR]

[Display omitted] • The coupled system achieved a maximum nitrogen removal efficiency of 97.8%. • Decreasing thiosulfate and raising nitrogen load boosted functional species growth. • Microbial cross-feeding and self-adaptation strategies were key mechanisms. A coupled thiosulfate-driven denitrification and anammox (TDDA) process was established to remove nitrogen from wastewater. It was optimized in an up-flow anaerobic sludge blanket reactor using synthetic wastewater, and its reliability was then verified with actual wastewater. The results demonstrated that nitrate, nitrite, and ammonium could be synergistically removed, and the highest total nitrogen removal efficiency reached 97.8% at a loading of 1.39 kgN/(m3·d). Anammox bacteria, primarily Candidatus_Brocadia , were the main contributors to nitrogen removal, while sulfur-oxidizing bacteria such as Thiobacillus and Rhodanobacter played a supportive role. By optimizing substrate conditions to enhance the anammox process, the coupled system attained higher abundances of functional genes such as napA , nirS , hzs , soxXA , and soxYZ , along with the corresponding microbial species. The data suggested that microbial cross-feeding and self-adaptation strategies were key to efficient nitrogen removal by TDDA. [ABSTRACT FROM AUTHOR]

Sulfur autotrophic denitrification (SADN) is regarded as a cost-effective bioremediation technology for nitrate-contaminated water. Nevertheless, the low bioavailability of sulfur is a major challenge that hinders nitrogen removal efficiency. A sulfur autotrophic disproportionation (SADP) process was proposed to convert sulfur to biogenic sulfide, greatly increasing the availability of electron donors. Throughout the 201-day laboratory-scale test, it was observed that the SADP process achieved desirable performance with 198.87 ± 39.8 mg S/L biogenic sulfide production per day, which could provide sufficient electron donors for the SADN process in treatment of 671.22 ± 134.40 mg N/L/d nitrate. Microbial community analysis confirmed the presence and dominancy of sulfur-disproportionating bacteria (SDB) (e.g., Desulfocaspa sp. taking up to 8.27% of the entire microbial community), while Thiobacillus was the most dominant genus of sulfur oxidizing bacteria (SOB), accounting for 87.32% of the entire community. Further experiments revealed that the addition of chemical and biogenic sulfides enhanced the nitrate removal rate of the SADN process by a factor of 1.31 and 1.34, respectively. Additionally, biogenic sulfide was found to be the most effective nitrous oxide (N 2 O) mitigator, reducing emission by 82% and 95% in denitrification and denitritation processes, respectively. The results demonstrated that the integrated SADP and SADN processes was a more effective and carbon-neutral alternative in treatment of nitrate-contaminated water. [Display omitted] • A stable biogenic sulfide production was achieved in the SADP-FBR. • Desulfocaspa was the predominant SDB (8.27%) in the SADP-FBR. • Thiobacillus was the predominant SOB (87.32%) in the SADN-FBR. • Addition of chemical and biogenic sulfides accelerated NO 3 − removal. • Biogenic sulfide greatly decreased N 2 O production compared to chemical sulfide. [ABSTRACT FROM AUTHOR]

• Sulfide addition promoted granulation of anammox sludge. • Sulfide addition favored EPS secretion, nuclei formation, and filamentous bacteria bridging. • Granules exhibited remarkable tolerance to environmental stress. • Anammox bacteria occurred in granules, while SOB proliferated in flocs. • Collaboration between heterogeneous granules-flocs endowed an efficient nitrogen removal. The granular anaerobic ammonium oxidation (anammox) system has attractive advantages in tolerance to environmental-stress and enhancement of nitrogen removal capacity. Sulfide addition can improve nitrogen removals in anammox systems via inducing sulfur denitrification, yet its function in the improvement of the property of anammox granular sludge remains unclear. Herein, we investigated the variations in the morphological and microbial properties of the anammox sludge response to different sulfide concentrations (Na 2 S: 10–100 mg/L) through a long-term experiment. By comparing the sludge diameter and heme c content, it comes that a relatively low sulfide (S/N [nitrate] molar ratio of 0.18–0.50) significantly promoted the average diameter and heme c concentration of sludge by 25–175 % and 75–95 %, respectively, compared to that of both without sulfide addition and a high sulfide addition (S/N > 0.85). This enhancement is primarily because a low amount of sulfide had stimulated the secretion of extracellular polymeric substance, induced slight biogenic sulfur accumulation as microbial nuclei, and facilitated the appropriate amount of filamentous bacteria proliferation. Microbial metabolism functions analyses revealed a robust granular anammox coupled with sulfur denitrification in the sulfide-mediated anammox reactor, and the assembled granules exhibited exceptional tolerance to environmental stress. Significantly, the anammox bacteria (Candidatus_ Brocadia) dominating the granules displayed satisfactory anammox activity (21.8 ± 2.1 mg N/g VSS h), and their produced nitrate was efficiently removed by the sulfur-oxidizing bacteria (Thiobacillus) that predominantly occurred in the flocs. This collaboration ensured an efficient sulfide-mediated anammox granules system, achieving nitrogen removal efficiency exceeding 95 %. These results highlight the function of sulfide in improving the morphological property of anammox sludge as well as the creation of a favorable ecological niche for the functional microorganism, which is important to maintain the efficiency and robustness of the anammox process in treating wastewater. [Display omitted] [ABSTRACT FROM AUTHOR]

Sulfate reducing anaerobic ammonium oxidation (S-Anammox) is a novel biological process that involves the oxidation of NH 4 + coupled with the reduction of SO 4 2−. This process has been observed under both inorganic and organic conditions; however, the nitrogen removal performance and the specific functional species in these two contexts remain poorly understood. Furthermore, the simultaneous occurrence of coupled sulfate reduction and sulfide oxidation adds complexity to the understanding of nitrogen and sulfur conversions. This study conducted a comparative analysis of the effects of inorganic and organic conditions on S-Anammox. The results demonstrated that the inorganic treatment exhibited a higher NH 4 +-N removal rate and activity (0.11 kgN/(m3 d) and 1.10 mgN/(gVSS h)) compared to the organic treatment (0.04 kgN/(m3 d) and 0.34 mgN/(gVSS h)). The sulfur cycle was particularly evident in the inorganic treatment, which showed a limited sulfate reduction rate of 0.02 kgS/(m3 d). More sulfate was removed in the organic treatment, resulting in an increase in the retention of sulfur (from 0.8% to 6.0%) in the sludge. qPCR analysis revealed that organic matter inhibited the abundances of key genes involved in ammonia oxidation (amo A and hao) and sulfide oxidation (sox B). Inorganic conditions are more favorable for S-Anammox. Sulfate reducing bacteria such as Desulfococcus multivovans and unidentified species, along with sulfide oxidizing bacteria including Comamonas flocculans , Candidatus Desulfobacillus denitrificans, and Thiobacillus denitrificans , were identified as contributors to the enhancement of the sulfur cycle under inorganic conditions. [Display omitted] • Inorganic conditions were more favorable for S-Anammox. • Amo A, hao and sox B in autotrophic microorganisms were inhibited by organic matters. • S-Anammox microorganisms were different for inorganic and organic conditions. • Organic matter diminished the diversity of autotrophic SOB. [ABSTRACT FROM AUTHOR]

[Display omitted] • Using pretreated stalk in-situ loaded S-NZVI to remediate actual low C/N water body. • Stalk is crucial for TN removal by supplying carbon source to microorganisms. • S-NZVI is crucial for TP removal by forming Fe-P precipitation. • Pretreated stalk acts as a scaffold to improve dispersity and O 2 resistance of S-NZVI. • S-NZVI and Pretreated stalk synergistically boost sediment microbial activity. Sulfidated nano zero-valent iron (S-NZVI) as reductants coupled with organic carbon are promising in enhancing denitrification which is crucial for remediation of low C/N water body. Nevertheless, the dearth of research on the effectiveness of these materials in actual water remediation limits their application. Additionally, most of the studies utilizes industrial chemical-derived organic carbon, which exacerbates environmental and economic burdens. This study proposes employing pretreated stalks in-situ loaded S/Fe (SS-S/Fe) to remediate the low C/N slightly black-odorous water body. The pretreated stalk acts as carbon source replacing the industrial chemicals. The pretreatment process was carried out by using H 2 O 2 and acetic acid to decrease the lignin content. The 2, 4-dichlorophenol was utilized as a target pollutant for optimization of materials. The sediment from the water body was remediated, the impact of SS-S/Fe on water body and microbial community structure were clarified. The lignin residues in the stalk were found to enhance the dispersity, O 2 resistance, and reduction performance toward 2, 4-dichlorophenol of S/Fe. S/Fe facilitates 2, 4-dichlorophenol degradation via reduction and TP removal via forming Fe-P precipitation. SS plays a significant role in TN removal, assisting in enhancing the 2, 4-dichlorophenol and TP removal performance of S/Fe. Crucially, SS and S/Fe synergistically boost sediment microbial activity, conferring resistance to the subsequent pollution shock. The decisive role of SS in enhancing denitrification by cultivating Anaeromyxobacter , unclassified_f_Comamonadaceae , norank_f_norank_o_norank_c_Anaerolineae and Thiobacillus has been demonstrated. This study improves S-NZVI applicability in actual low C/N water bodies and provides new methods for utilizing stalk resources. [ABSTRACT FROM AUTHOR]

[Display omitted] • Original IS had lower denitrification and S cycle genes in IS than those of AS. • Biofilm inoculated by IS enriched more functional genes than by AS in SAD systems. • Biofilm domesticated by IS had more S cycle genes at high stress of S2- and SO 4 2- • Microbes for S cycle more sensitive to the toxicity of S2- than denitrifiers. To develop a reliable sulfide (S2-) autotrophic denitrification (SAD) process under S2- and SO 4 2- salinity stresses, the biofilm performance and microbial mechanisms were comparatively studied using different inocula of activated sludge (AS) and intertidal sediment (IS). Biofilm IS enriched more denitrification genes (0.34 %) and S2- oxidation genes (0.29 %) than those with AS. Higher denitrification performance was obtained under S2- (100 mg/L) and SO 4 2- (5–15 g/L Na 2 SO 4) stresses, but no significantly differences were observed under levels of 0–200 mg/L S2- and 30 g/L Na 2 SO 4. Notably, biofilm samples in SAD systems with IS still had more S2- oxidation genes at high S2- levels of 100–200 mg/L and Na 2 SO 4 level of 30 g/L. The key functional genus Thiobacillus accumulated well at 30 g/L Na 2 SO 4 , but was strongly inhibited at 200 mg/L S2-. The findings were advantage to SAD application under sulfide and salinity stresses. [ABSTRACT FROM AUTHOR]

A high rate of elemental sulfur (S0) accumulation from sulfide-containing wastewater has great significance in terms of resource recovery and pollution control. This experimental study used Thiobacillus denitrificans and denitrifying bacteria incorporated with signal molecules (C6 and OHHL) for simultaneous sulfide (S2–) and nitrate (NO3–) removal in synthetic wastewater. Also, the effects on S0 accumulation due to changes in organic matter composition and bacteria proportion through signal molecules were analyzed. The 99.0% of S2– removal and 99.3% of NO3– was achieved with 66% of S0 accumulation under the active S2– removal group. The S0 accumulation, S2– and NO3– removal mainly occurred in 0–48 h. The S0 accumulation in the active S2– removal group was 2.0-6.3 times higher than the inactive S2– removal groups. In addition, S0/SO42- ratio exhibited that S0 conversion almost linearly increased with reaction time under the active S2– removal group. The proportion of Thiobacillus denitrificans and H+ consumption showed a positive correlation with S0 accumulation. However, a very high or low ratio of H+/S0 is not suitable for S0 accumulation. The signal molecules greatly increased the concentration of protein-I and protein-II, which resulted in the high proportion of Thiobacillus denitrificans. Therefore, high S0 accumulation was achieved as Thiobacillus denitrificans regulated the H+ consumption and electron transfer rate and provided suppressed oxygen environment. This technology is cost-effective and commercially applicable for recovering S0 from wastewater. [ABSTRACT FROM AUTHOR]

The Biological Sulfur Recovery Unit (BSRU) with Thiobacillus as biocatalysts is believed to be suitable for handling soluble sulfur in wastewater. The purpose of this study is to evaluate the effect of nutrient (SO42−, PO43−, and Fe2+) concentration on BSRU performance, particularly on the conversion of sulfide to elemental sulfur. This study shows that the variation of SO42− concentration does not significantly affect the conversion process, while a small increment of PO43− (KH2PO4 1.7 g/L and K2HPO4 1.36 g/L) results in a higher yield of elemental sulfur production. Fe2+ also significantly affected the formation and conversion rate of elemental sulfur. [ABSTRACT FROM AUTHOR]

Biological treatment processes are an effective method for removing the nitrogen-containing contaminants that exist in coking wastewater. However, little is known about microbial composition and keystone taxa involved in biological nitrogen removal processes. In order to improve the removal efficiency of nitrogen-containing contaminants in anaerobic-aerobic-hydrolytic-aerobic (A/O1/H/O2) system, the microbial composition and interactions of keystone taxa should be clarified. The present work clarifies the removal performance of nitrogen-containing contaminants in the A/O1/H/O2 system, identifies the microbial community involved in various bioreactors, and reveals the keystone taxa within the microbial communities. Combined the processes of ammoniation, denitrification, and nitrification, total nitrogen decreased from 248 to 31 mg L−1 and achieved a removal efficiency of 87.5% in the full-scale A/O1/H/O2 system. High-throughput MiSeq sequencing revealed that Proteobacteria was the most abundant phylum in the A/O1/H/O2 system with relative abundances of 24%–50%. Thiobacillus dominated in bioreactors A and O1 with relative abundances of 2.90% and 4.44%, respectively, while Nitrospira was identified as the most dominant genus in bioreactors H and O2, accounting for 13.33% and 18.38%, respectively. The microbial community composition and co-occurrence network analysis showed that the keystone taxa belonged to Thiobacillus, Nitrospira, Bdellovibrio, Planctomyces, Desulfotomaculum , and Sphingobium , which are related to nitrogen degradation. [ABSTRACT FROM AUTHOR]

Fertilization managements have important impacts on soil P transformation, turnover, and bioavailability. Thus, long-term fertilization experiments (~38 years) with the application of different inorganic and organic fertilizers in paddy red soils were conducted to determine their effect on P pool accumulation and microbial communities, especially for phosphate solubilizing microorganisms (PSM). Long-term inorganic P fertilization increased the concentrations of total P (~479 mg/kg), available P (~417 mg/kg), and inorganic P (~18 mg/kg), but manure fertilization accelerated the accumulation of organic P, especially for orthophosphate monoesters (e.g. myo-IHP, ~12 mg/kg). Long-term mineral fertilization decreased bacterial richness, evenness, and complexation of bacterial networks. In contrast, long-term manure fertilization and rhizosphere accumulated more amounts of total carbon, total nitrogen, and organic carbon, as well as regulated the soil pH, thus improving the separation of bacterial communities. Unlike bacteria, the responses of fungi to those factors were not sensitive. Furthermore, PSM compositions were greatly influenced by fertilization managements and rhizosphere. For example, inorganic P fertilization increased the abundance of Thiobacillus (i.e. the most abundant phosphate solubilizing bacteria (PSB) in this study) and shifted the community structure of PSB. Correspondingly, the concentrations of inorganic and total P were the key factors for the variation of PSB community structure. These findings are beneficial for understanding P accumulation, responses of PSB, and soil P sustainable fertility under different fertilization strategies. [ABSTRACT FROM AUTHOR]

Background: Remediation of petroleum hydrocarbons from the soil is one of the essential factors. This study was conducted to test the impact of sulfur granular Municipal Soil Waste (sulfur granular MSW), foliar application of iron sulfate on biodegradation of diesel oil in a cadmium (Cd)-polluted soil in the presence of thiobacillus bacteria.Methods: Treatments consisted of applying sulfur granular MSW at the rates of 0 and 15 t/ha and foliar application of iron sulfate (0 and 500 mg/L) in a Cd-polluted (0, 10, and 20 mg Cd/kg) soil that simultaneously contaminated with diesel oil (0%, 4%, and 8% w/w) in the presence of thiobacillus bacteria. After 60 days, the corns were harvested, and the plants’ Fe and Cd concentration was measured using Atomic Absorption Spectroscopy (AAS). In addition, thebiodegradation of diesel oil in the soil was measured.Results: Soil application of sulfur granular MSW (15 t/ha) significantly increased the biodegradation of diesel oil in the soil by 16.1%. However, soil contamination with Cd had an adverse effect on the biodegradation of diesel oil in the soil. The presence of thiobacillus bacteria had a considerable effect on reducing the Fe and Cd concentration of the plant by 16.1% and 17.3%, respectively.Conclusion: Based on the study results, using sulfur granular MSW and foliar application of iron sulfate has a significant effect on the biodegradation of diesel oil in the heavy metal polluted soil. However, the role of plant physiology, the type, and the amount of pollution on phytoremediation efficiency cannot be ignored.

The heterotrophic and autotrophic synergistic denitrification (HAD) system can effectively remove sulfide, nitrate, and organic carbon pollutants from municipal wastewater. However, the effect of sulfide on the functional bacteria in the denitrification system is still unclear. To better understand the mechanism of sulfide affected on bacteria in the system, the up-flow anaerobic sludge blanket (UASB) reactor was operated continuously under heterotrophic (no sulfide added) and mixotrophic conditions (with increased sulfide contents) for 120 days. The contents of protein (PN) in extracellular polymeric substances (EPS) were significantly increased with the addition of sulfide, which enhanced the flocculation of sludge and was beneficial to the formation of high-density microorganism communities. The dominant bacteria showed large differences under different nutrient conditions. The abundances of Thauera increased from 4.13% to over 12.94%, and that of Dechloromonas and Thiobacillus were 2.61–3.01% and 1.04–2.66% respectively after added sulfide. And the efficient performance of the system in mixotrophic conditions was accomplished with the interaction of heterotrophic sulfide-oxidizing, nitrate-reducing bacteria (Thauera, Dechloromonas), autotrophic sulfide-oxidizing, nitrate-reducing bacteria (Thiobacillus) and heterotrophic nitrate-reducing bacteria (Rubrivivax, Acidovorax, Simplicispira, Alicycliphilus). Moreover, the abundances of Nar G, Nap A, Nir S, Nor B, and Nos Z were significantly enhanced in mixotrophic conditions, indicating that the nitrogen metabolism potential of the system was also improved after added sulfide. These results elucidated the reasons for the enhanced denitrifying capacity of the system by adding S2− from the microbiological point of view and provided a theoretical basis for the establishment of an efficient denitrification system. [ABSTRACT FROM AUTHOR]

Nitrate contamination of groundwater and surface water has become a serious problem. Zero-capacity iron (Fe0) nanoparticles are of great interest for the purification of toxic compounds from water. The aim of this study was to synthesis and optimize starch-coated "St" and carbon quantum dot-coated "CQD" Fe0 nanoparticles (St-Fe0 and CQD-Fe0) and investigate their role in bio denitrification and expression of nirS, narH and recA genes using the q-PCR technique. This study has a non-treatment control. The structural and morphological characteristics of nanoparticles were determined by XRD, TEM, FE-SEM and FTIR. Two important operating parameters including temperature (̊C) and nanoparticles concentration (g l−1) influencing the bio denitrification process of Thiobacillus denitrificans in the presence of nanoparticles were optimized by the response surface method (RSM). The FTIR spectrum confirmed the formation of CQD-Fe0 bonds. The average diameter of CQD-Fe0 nanoparticles was in the range of 29.31 to 38.32 nm. Denitrification in the presence of St-Fe0 and CQD-Fe0, with increasing temperature (35 C°) and nanoparticle concentration (1 g l−1), was 71.42% and 73.43%, respectively. After determining the optimal conditions, bio denitrification in the presence of nanoparticles at different concentrations of nitrate was investigated in a moving bed bioreactor. According to the results, in the discontinuous conditions, bio denitrification efficacy of Thiobacillus denitrificans in the presence of St-Fe0 and CQD-Fe0 nanoparticles was 80.10% and 79.83%, respectively. While in the bioreactor, denitrification efficacy in the presence of St-Fe0 and CQD-Fe0 was increased to 94.07% and 95%, respectively. In other words, bio denitrification of microorganisms in the moving bed bioreactor in the presence of CQD-Fe0 was higher compared to St-Fe0. The results of this study showed that the expression of all three genes nirS, narH and recA in cells treated with St-Fe0 and CQD-Fe0 significantly increased compared to the control group, which indicates the high impact of these nanoparticles, especially CQD-Fe0 on bio denitrification of this microorganism. [ABSTRACT FROM AUTHOR]

• Sulfur consumption rates are dependent on nitrate concentration. • Coagulants interfere with sulfur utilization by sulfur-denitrifying microorganisms. • 3 M coagulant reduces sulfur denitrification efficiency and leads to nitrite accumulation. • Excessive coagulant injection is lethal to Sulfurimonas but not to Thiobacillus. The integration of elemental sulfur-based autotrophic denitrification with membrane bioreactor (MBR) technology offers a cost-effective solution for nitrate removal; however, stable operation demands efficient sulfur utilization and phosphorus management. This study explores sulfur consumption dynamics and the impacts of coagulant injection on denitrification efficiency. Sulfur consumption was closely correlated with nitrate removal rates, highlighting the critical role of stoichiometric sulfur availability for sustained denitrification. While coagulant addition enhanced phosphorus removal, excessive dosing impaired elemental sulfur-based microbial activity, reducing nitrate removal efficiency and increasing nitrite accumulation. Notably, microbial community analysis revealed a decline in the abundance of key sulfur-oxidizing bacteria, such as Sulfurimonas, under high coagulant concentrations. These findings emphasize the need for optimized sulfur and coagulant dosing strategies to balance phosphorus and nitrate removal while preserving microbial diversity and reactor stability. This study provides practical insights into operational parameters for efficient and sustainable ESAD-MBR processes. [ABSTRACT FROM AUTHOR]

[Display omitted] • Biofilm predominated nitrogen removal in anammox-PS0AD coupled system. • Biofilm exhibited distinct spatial niche differentiation. • Candidatus Brocadia is the dominated anammox species in the presence of S0. • N-S cycle was achieved through anammox, PS0AD and sulfammox processes. • Metagenome analysis revealed variations of key genes in the coupled system. Anammox coupled partial S0-driven autotrophic denitrification (PS0AD) technology represents an innovative approach for removing nitrogen from wastewater. The research highlighted the crucial role of biofilm on sulfur particles in the nitrogen removal process. Further analysis revealed that sulfur-oxidizing bacteria (SOB) are primarily distributed in the inner layer of the biofilm, while anammox bacteria (AnAOB) are relatively evenly distributed in inner and outer layers, with Thiobacillus and Candidatus Brocadia being the dominant species, respectively. Except for anammox and PS0AD processes, 15N isotope labeling tests determined that sulfur reshaped nitrogen metabolism pathways, providing solid evidence for the occurrence of sulfammox process. SOB and AnAOB collaborate in nitrogen and sulfur conversion, with SOB-drived PS0AD processes reducing nitrate to nitrite for AnAOB to remove ammonia. Conversely, the nitrate produced from anammox process can be reused by SOB. Metagenomic analyses verified that SOB drove the PS0AD process through encoding soxBYZ gene, while AnAOB might play an important role in simultaneously driving the anammox and sulfammox processes. These findings underscore the importance of biofilm and clarify the nitrogen-sulfur cycle mechanisms within the coupled system. [ABSTRACT FROM AUTHOR]

Sulfur-oxidizing bacteria (SOB) play a vital role in the occurrence of sulfur oxidation intermediate (SOI) compounds often recalcitrant to currently available, abiotic treatment within metal mine tailings impoundments (TI). As inadvertent SOI discharge post-treatment can lead to the uncontrolled acidification of receiving environments, it becomes increasingly important to elucidate the environmental controls on SOB identities and sulfur cycling within these relatively unstudied systems. Here, results identified controlling factors on SOB community differentiation and associated metabolic pathway occurrence through integrated physicochemical, geochemical, and microbial field and experimental investigation across three summers (2016, 2017, 2021) in a stratified Northern Ontario base metal TI. Dynamic shifts in SOB communities and sulfur oxidation pathways were primarily driven by [S 2 O 3 2−] and further influenced by pH, [O 2 ], and conductivity. At [S 2 O 3 2−] above 0.03 mM, Halothiobacillus spp. was observed to dominate in lower pH, higher conductivity conditions where complete SOI oxidation, mediated through the complete Sox pathway, is suggested to reduced [SOI] in treated discharge waters. At [S 2 O 3 2−] below 0.03 mM, an SOB assemblage (Thiovirga spp., Thiobacillus spp., and Sediminibacterium spp.) was observed to collectively dominate under higher pH and lower conductivity, associated with SOI persistence due to SOI recycling pathways (incomplete Sox, rDSR, S 4 I). Targeted SOB enrichment cultures confirmed the importance of S 2 O 3 2− availability in driving SOB community shifts and the capability of Halothiobacillus to outcompete other SOB under oxygenated, high [S 2 O 3 2−] conditions. Trends observed here for mine TI associated SOB were found to also occur across a broader suite of contexts using literature data, indicating their wider ecological relevance in interpreting outcomes associated with SOB activity. Results also provide new insights into improved, biologically informed management of sulfur associated risks with potential SOB manipulation through [S 2 O 3 2−], pH, and/or [O 2 ] controls. [Display omitted] • Sulfur oxidation intermediate compounds (SOI) pose risks to receiving environments. • Extent of microbial S transformations in tailings impoundments driven by [S 2 O 3 2−]. • [S 2 O 3 2−] > 0.3 mM favors sole Halothiobacillus domination and decreased S risks. • [S 2 O 3 2−] < 0.3 mM favors an SOB assemblage and persistent S compounds. • PH, [O 2 ], and conductivity further influence SOB type and thus S risks. [ABSTRACT FROM AUTHOR]

[Display omitted] • Polarity reversal acclimated biocathode promote para -dechlorination. • Dechlorination and mineralization of 2,4,6-TCP occurred simultaneously at the anaerobic biocathode. • Acclimated biocathode allowed bidirectional electron transfer. • Mycobacterium involved in bidirectional electron transfer and degradation of chlorophenols. In the anaerobic biocathode, reductive dechlorination of 2,4,6-trichlorophenol (2,4,6-TCP) mainly proceeded to produce 4-monochlorophenol (4-MCP) and phenol, while anaerobic mineralization was challenging. In this study, biocathodes microbial communities were first acclimated via potentials repeatedly adjusted between −0.278 V and +0.200 V (T-200), −0.278 V and +0.400 V (T-400), and −0.278 V and +0.600 V (T-600). Subsequently, all biocathode potentials were stabilized at −0.278 V for the degradation of 2,4,6-TCP. The results revealed that the T-600 achieved the highest degradation rate of 2,4,6-TCP (0.43 d−1), outperforming T-200 (0.051 d−1), T-400 (0.020 d−1), and open-circuit bioreactor (OC, 0.038 d−1) groups. In T-600, pare -dechlorination was facilitated, allowing for the conversion of 2,4,6-TCP to 2-monochlorophenol (2-MCP). Additionally, the detection of 4-hydroxybenzoic acid, an anaerobic mineralization intermediate of 2,4,6-TCP, indicated that anaerobic mineralization was also occurring. Polarity reversal occurred only in T-600 during the acclimation period, resulting in alterations to the electrical properties of the biocathode and microbial community. The cyclic voltammetry (CV) and differential pulse voltammetry (DPV) results indicated that there were more electroactive sites in biocathode of T-600, and the bidirectional extracellular electron transfer (EET) might be related to cytochrome. Mycobacterium (24.33% in slurry and 19.92% in biofilm), Thiobacillus (2.47% in slurry and 17.85% in biofilm), and Arenimonas (4.23% in slurry and 4.32% in cathode biofilm) were identified as the dominant electroactive bacteria in T-600, with Mycobacterium also playing an important role in the degradation of chlorophenols. These findings suggested that polarity reversal may represent a viable strategy for constructing microbial communities capable of achieving simultaneous dechlorination and mineralization of 2,4,6-TCP. [ABSTRACT FROM AUTHOR]

[Display omitted] • An approach in MBfR of novel SDMO system was successfully built and operated for ∼ 200 days. • SBR-MBfR showed superior performance compared to the EGSB-MBfR. • Random Forest regressor was demonstrated to be the optimal model for SDMO. • A hidden positive correlation between DAMO bacteria and Thiobacillus was uncovered. Traditional denitrification process consumes external organic carbon leading to an increase in treatment costs and carbon emission. A novel sulfide-driven denitrification methane oxidation (SDMO) system, which could simultaneously utilize CH 4 and H 2 S in biogas as electron donors for denitrification to reduce the cost and carbon emission, has been successfully operated in two kinds of reactors SBR-MBfR and EGSB-MBfR for ∼ 200 days in this study. The performance and microbial community were explored meanwhile machine learning approach have been used for predicting the complex effects on SDMO's denitrification efficiency. Result shows SBR-MBfR's superior performance with the maximum nitrate removal efficiency > 90 % while the denitrification rates and biological activity were also better than EGSB-MBfR. The autotrophic denitrification (Auto-D) contributed 5 % much more for nitrate removal in SBR-MBfR than EGSB-MBfR while denitrification anaerobic methane oxidation (DAMO) was more prominent in EGSB-MBfR. Nineteen machine learning models were used for operation data training and random forest regressor was demonstrated to be the optimal model for predicting nitrate removal efficiency in SDMO. According to random forest regressor's analysis, HRT presented the highest importance in affecting SDMO nitrate removal efficiency. After the introduction of biogas for domestication, Auto-D bacteria Thiobacillus was the dominant bacteria in both systems occupying > 20 % and the abundance would increase gradually from ∼ 20 % to ∼ 60 % as H 2 S content rising. A hidden positive correlation between DAMO bacteria Candidatus Methylomirabilis and Thiobacillus was uncovered by mantel test analysis here, implying the integrating of Auto-D and DAMO process for nitrate removal. This study not only provides insights into the novel SDMO technology but also offers a potential advancement in simultaneously low-carbon wastewater treatment and biogas utilization. [ABSTRACT FROM AUTHOR]

[Display omitted] • An efficient HNAD was successfully initiated by thiosulfate and sodium acetate. • PCMX improved but BEC and mixed disinfectants inhibited denitrification activity. • PCMX elevated the levels of EPS, which was damaged by BEC and mixed disinfectants. • P-HSAD had the most enriched iRGs, and PB-HSAD led to a more complex spread of RGs. • Reduced Sulfurimonas led to inhibition of denitrification in B-HSAD and PB-HSAD. The effects of typical disinfectants chloroxylenol (PCMX) and benzethonium chloride (BEC) on heterotrophic/sulfur autotrophic denitrification (HSAD) systems under single and mixed stress were studied. PCMX increased the system's denitrification activity, but BEC and mixed disinfectants, particularly mixed disinfectants, significantly reduced denitrification activity. PCMX elevated the content of extracellular polymeric substances (EPS) in HSAD system, and the structure of EPS was tight and stable. Whereas the other two systems had lower EPS content and looser structure, highlighting the greater damaging effects of BEC and mixed disinfectants. PCMX led to the enrichment of more than half of the resistance genes (RGs), while mixed disinfectants resulted in the fewest RGs enriched and the lowest correlations between bacteria and RGs of three systems. The transformation of extracellular qacE was induced by PCMX. BEC caused RGs to leak out of bacteria, and mixed disinfectants contributed to transformation and efflux of RGs. PCMX increased the abundance of Thiobacillus and Sulfurimonas. Thiobacillus was more abundant in low doses of BEC and mixed disinfectants, but it reduced at high concentrations, while the amount of Sulfurimonas continued to decrease. This study provided an insight into the effects of single and mixed disinfectants on HSAD systems, and guided future efforts to control disinfectants and RGs pollution in wastewater treatment. [ABSTRACT FROM AUTHOR]

[Display omitted] • The accumulation efficiency of NO 2 −-N and S0 reached 89.40% and 93.41%, respectively. • O 2 changes the ORP value, leading to a decrease in the accumulation of S0 and NO 2 −. • O 2 entry accelerates the oxidation of S2−, but limits the reduction of NO 3 −-N. • DO promoted the synergistic effect of Thiobacillus and Azoarcus without Nitrospia. Understanding the effect of O 2 on the accumulation characteristics of NO 2 −-N and S0 in the sulfur autotrophic denitrification (DSSADN) system is crucial for enhancing the denitrification efficiency of partial nitrification-anammox using DSSADN. The results revealed that in an environment without O 2 entry, the NO 2 −-N accumulation efficiency (NiAE) and S0 accumulation efficiency (S0AE) of the DSSADN system reached 89.40 % and 93.41 %, respectively. Once system entered O 2 , ORP value kept increasing. When ORP increased to −59.9 mV (DO = 0.1 mg/L), soxB and nirK gene expression rose and as well NiAE and S0AE continuously decreased to 48.13 % and 29.35 %. When ORP was above 30.9 mV (DO >0.2 mg/L) but below 81.0 mV (DO<0.4 mg/L), narG gene expression reduced and the relatively high sqr gene expression allowed NiAE and S0AE remained at 45.08 % and 33.31 %. O 2 promoted the synergistic effect of Thiobacillus and Azoarcus without the proliferation of nitrite oxidizing bacteria. [ABSTRACT FROM AUTHOR]

[Display omitted] • Targeted treatment of nitrate groundwater was achieved without deterioration. • S0 as electron donor-driven MFC has high electron utilization rate and economic. • Flavin and cytochrome c as electron mediators for accelerating electron transfer. • Current additionally encouraged changes in the protein's secondary structure. • Thiobacillus and Desulfocapsa as main genus contributed to denitrification. Sulfur (S0)-driven autotrophic denitrification system has obvious advantages in economy and performance in treating the low carbon/nitrogen groundwater. However, the by-products produced from S0 oxidation will cause disturbance to the water quality. In this study, a dual-chamber microbial fuel cell was driven by S0 (S0-MFC) to separate the S0 and nitrate, the electrons generated by the oxidation of S0 in the anodic chamber transferred to the cathode for nitrate reduction. Under the action of the anode microorganisms, the S0 was directly oxidized to sulfate. The maximum nitrate removal rate (NRR) in the cathodic chamber was 2.31 ± 0.03 mg N/L/h, and the anode electron utilization rate could reached to 19.69 %. Electrochemical results showed that flavin and c-type cytochrome could acted as electron mediators promote the electron transfer processes. The presence of loop current contributed to the enhancement of microbial metabolic activity, thus improving the stability of sludge and NRR. The denitrifiers (Thiobacillus and Denitratisoma) and sulfur autotrophs (Desulfocapsa and Acidithiobacillus) played an important role in the high NRR. A low-cost and pollution-free method for removing nitrate from groundwater was realized in this study. [ABSTRACT FROM AUTHOR]

[Display omitted] • Evidence for direct electron transfer denitrification (DETD) was observed. • The nitrogen removal rate reached 60.17 mmol NO 3 −-N L−1 day−1 m−2. • Thiobacillus highly expressed extracellular multiheme c -type cytochrome genes. Cathodes can play a pivotal role as electron donors for denitrification in wastewater treatment plants, facilitating the removal of nitrogen-containing compounds such as nitrate. Denitrifying bacteria can either accept electrons directly from the electrode or indirectly via electron shuttling intermediaries generated at the cathode. In this study, comparative analyses were conducted between two denitrifying electrochemical reactors with biocathodes poised at different potentials, one that generated H 2 through water electrolysis and one that did not (−500 mV and −800 mV vs. SHE). Nitrogen removal efficiencies were much higher in the −500 mV (vs. SHE) system, >93 % compared to only 20 %. Notably, a biofilm formed exclusively on the −500 mV (vs. SHE) cathode, predominantly composed of Thiobacillus species, with the majority most similar to Thiobacillus strain 65-29. Metatranscriptomics showed that genes from Thiobacillus strain 65-29 encoding outer surface c -type cytochrome and porin proteins that could facilitate direct electron uptake, were markedly up-regulated in the −500 mV (vs. SHE) reactor. Reduced sulfur species generated by the cathode and sulfate reducing bacteria might have also provided a source of electrons for nitrate reduction. In fact, Thiobacillus in the −500 mV (vs. SHE) system exhibited elevated expression of genes involved in thiosulfate (soxABXYZ), sulfite (soeABC), and sulfide (fccAB) oxidation. These findings offer valuable insights into the mechanisms of autotrophic denitrification by Thiobacillus in mixed culture systems and provide practical guidance for engineering applications. [ABSTRACT FROM AUTHOR]

Purpose: Sulfate-reducing bacteria (SRB) are recognized by scholars as the most important class of bacteria leading to corrosion of metal materials. It is important to use the properties of microorganisms to inhibit the growth of SRB in the corrosion protection of metal materials and to protect the environment. Design/methodology/approach: In this work, the behavior of anaerobic Thiobacillus denitrificans (TDN) intracellular enzyme inhibition of SRB corrosion of EH36 steel was investigated with electrochemical impedance spectroscopy, biological detection technology and X-ray photoelectron spectroscopy. Findings: Results showed that the SRB crude intracellular enzyme affected the corrosion behavior of EH36 steel greatly and the purified TDN intracellular enzyme inhibits SRB intracellular enzyme corrosion to EH36 steel. Originality/value: A perfect enzyme activity inhibition mechanism will provide theoretical guidance for the selection and application of anticorrosion microorganisms, which is of scientific significance in the field of microbial anticorrosion research. [ABSTRACT FROM AUTHOR]

The diversity, community structure and vertical distribution characteristics of bacteria in the surface and subsurface soil and water samples of a closed landfill in Shanghai Jiading District were investigated to reveal the relationships between natural waste degradation degree and the succession of bacterial community composition. High-throughput sequencing of bacteria 16S rDNA genes was used to analyze the bacterial community structure and diversity. The results showed that the diversity of bacteria in the surface samples was higher than that in the deep samples. Proteobacteria was the dominant phylum in all the samples, and the percentage increased with depth. At the genus level, Thiobacillus, Pseudomonas, Aquabacterium, and Hydrogenophaga were the dominant genera in surface, medium, deep and ultra-deep soils, respectively. The Bray–Curtis dissimilarity of the soil bacterial communities in the same layer was small, indicating that the community composition of the samples in the same layer was similar. The RDA result showed that ammonium, nitrate, pH and C/N significantly influenced the community structure of soil bacteria. This is of great relevance to understand the effect of natural waste degradation on bacterial communities in closed landfills. [ABSTRACT FROM AUTHOR]

The biological study experiment included the effect of inoculation with sulphur-oxidizing bacteria T. thioparus and its interaction with levels of organic matter. In addition, a biological vaccine for T. thioparus and the second factor is the organic matter at three levels control by without adding (0%, 0.5%, 1 %) the results of the statistical analysis showed that the biological Inoculation. T. thioparus treatment gave the highest levels of grain yield, numbers of T. thioparus bacteria, soil content of available nitrogen and soil content of available sulphur (4.74 mg.h-1, 0.22×104 CFu gm-1 soil, 54.27 mg N kg soil-1, 3131.39 mg S kg soil-1) respectively. While treatment with the second level of organic matter 1% gave the highest levels of the numbers of T. thioparus bacteria and the nitrogen content available in the soil and the sulphur content available in the soil (0.23×104 CFu gm-1 soil, 5163 mg N kg soil-1, 2796 mg S kg soil-1) respectively. In addition to the interactive treatments of biological inoculation of T. thioparus and organic matter of B1O2 of T. thioparus numbers, nitrogen content available in soil and soil sulphur content available (0.24×104 CFu gm-1 soil, 59.40 mg N kg soil-1, 3326.87 mg S kg soil-1) respectively. [ABSTRACT FROM AUTHOR]

The purpose of this study is to clarify the mechanism of the coupled hydrion with biology polysulfide in the simultaneous denitrification and desulfurization process. The coupled hydrion with biology polysulfide, uncoupled hydrion with biology polysulfide and no polysulfide experiments were performed in wastewater with two kinds of sulfide loads (100 and 200 mg/L). When the concentration of thiosulfate was suitable, the free H+ concentration (74.2 and 91.0 mg/L) and the proportion of Thiobacillus denitrificans (85.4% and 59.7%) were both higher under the two kinds of sulfide loading conditions (100 and 200 mg/L), and coupled hydrion with biology polysulfide was realized (the production of elemental sulfur is as high as 33 and 101 mg/L). Further analysis shown that the way of coupled hydrion with biology polysulfide were both: 2.0 S 2 − + 6.4 NO 3 − + 30.1 H + + 21.7 e − → 1.0 S 2 − + 1.0 SO 4 2 − + 3.2 N 2 + 15.0 H 2 O . In addition, for the coupled hydrion with biology polysulfide, more nitrates could be utilized to produce elemental sulfur S0, and the lower ratio of H+/S0 and SO 4 2 − / S 0 were observed (S2- = 100 mg/L: 2.3 and 0.9; S2- = 200 mg/L: 0.9 and 0.03), which could promote the growth of Thiobacillus denitrificans and increase the proportion of Thiobacillus denitrificans. This maybe one of the reasons why coupled hydrion with biology polysulfide could be achieved. [ABSTRACT FROM AUTHOR]

In an agri-silviculture of the plum (Prunus domestica L. Cv. Opal), the forage quality of smooth vetch (Vicia dasycarpa L.) was evaluated. For this purpose, a two-year (2016 and 2017) factorial experiment was conducted based on randomized complete block design with three replications at Urmia University, Iran. The treatments included the combined and individual application of biofertilizers {Azotobacter chroococcum (Az), Thiobacillus spp. (Th)., Rhizophagus intraradices (AMF) and control} under rainfed and once supplementary irrigation. The results showed that irrigated plants contained higher P than rainfed plants. Dual inoculation with "AMF + Az" had higher Ash, K, CP and WSC than plants with fungal or bacterial inoculation alone. In comparison with control, biofertilizers improved the forage and protein yield by 32 and 45.50% under rainfed conditions and by 47 and 60.04% under supplementary irrigation, respectively. The amount of CAT, GR, APX, and SOD were reduced in rainfed plants, but the co-inoculation of mycorrhizal plants with Az and/or Th enhanced enzymatic antioxidants. In conclusion, the combined use of AMF and Az improved smooth vetch forage quantity and quality in irrigated plants as much as rainfed did, and hence it can be desirable for sustainable agriculture. [ABSTRACT FROM AUTHOR]

This work reports the possibility of uranium recovery from a post-mining uranium ore dump in Poland by a bioleaching method. The studies were conducted on the dump leaching model with the mass of 570 kg of uranium bearing mineral material from Radoniów pile and in the periodic bioreactor with a work volume of 80 dm3 and with mechanical mixing and aeration of the charge. The uranium concentration in the examined material was about 800 ppm. In this process, the consortium of microorganisms isolated from former mines was used. It was composed of the following microorganisms: Bacillius, Pseudomonas, Sphingomonas, Thiobacillus, Halothiobacillus, Thiomonas, and Geothrix. The efficiency of the uranium bioleaching process was 98% in the reactor, and a yield of 70% was obtained in the dump leaching model. The post-leaching solution contained significant amounts of uranium ions that were separated in two stages: (1) by ion chromatography and then (2) by a two-step precipitation method. The resulting solution was a source of ammonium diuranate, the precursor of yellowcake (uranium oxides). [ABSTRACT FROM AUTHOR]

In order to investigate the effect of organic and chemical fertilizers on quantitative and qualitative traits of Ducrosia anethifolia, a randomized complete block design was carried out with three replications. The experiment was performed with seven treatments including control (no fertilizer), manure (bovine), chemical fertilizers including nitrogen(N), phosphorus (P) and potassium (K), vermicompost fertilizer, thiobacillus bacterium, mycorrhiza fungi, and a combination of mycorrhizal fungi and thiobacillus bacterium (mycorrhiza+thiobacillus). Results showed that fertilizer treatments increased the yield and yield components of the plant compared to the control. Inoculation with thiobacillus, mycorrhiza, and thiobacillus+mycorrhiza resulted in higher levels of seed yield, essential oil yield and percentage, chlorophyll a, b and total and also carotenoids content compared to plants treated with chemical fertilizers. Generally, thiobacillus+mycorrhiza treatment led to more seed yield (8430 kg/ha) and essential oil yield (176.36 kg/ha) than other treatments, showing 62% and 52% increase in seed yield and 80% and 321% increase in essential oil yield in comparison with control and chemical fertilizers, respectively. Based on the results of this research, application of biological fertilizers can control excessive use of chemical fertilizers in sustainable agriculture. [ABSTRACT FROM AUTHOR]

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