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1.
Sci Total Environ ; 750: 141513, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32853935

RESUMO

Excessive nitrate in water systems is prevailing and a global risk of human health. Polluted river sediments are dominated by anaerobes and often the hotspot of denitrification. So far, little is known about the ecological effects of nitrate pollution on microbial dynamics, especially those in sulfide-rich sediments. Here we simulated a nitrate surge and monitored the microbial responses, as well as the changes of important environmental parameters in a sulfide-rich river sediment for a month. Our analysis of sediment microbial communities showed that elevated nitrate led to (i) a functional convergence at denitrification and sulfide oxidation, (ii) a taxonomic convergence at Proteobacteria, and (iii) a significant loss of biodiversity, community stability and other functions. Two chemolithotrophic denitrifiers Thiobacillus and Luteimonas were enriched after nitrate amendment, although the original communities were dominated by methanogens and syntrophic bacteria. Also, serial dilutions of sediment microbial communities found that Thiobacillus thiophilus dominated 18/30 communities because of its capability of simultaneous nitrate reduction and sulfide oxidation. Additionally, our network analysis indicated that keystone taxa seemed more likely to be native auxotrophs (e.g., syntrophic bacteria, methanogens) rather than dominant denitrifiers, possibly because of the extensive interspecific cross-feeding they estabilished, while environment perturbations probably disrupted that cross-feeding and simplified microbial interactions. This study advances our understanding of microbial community responses to nitrate pollution and possible mechanism in the sulfide-rich river sediment.


Assuntos
Microbiota , Rios , Desnitrificação , Sedimentos Geológicos , Nitratos , Sulfetos , Thiobacillus
2.
Sci Total Environ ; 748: 142445, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-33113701

RESUMO

Sulfur autotrophic denitrification utilizes elemental sulfur as the electron donor for nitrate removal from aquatic environments. Organic carbon could stimulate the conversion of sulfur and facilitates the S0-based denitrification process in the mix-trophic. In this study, the co-cultured system of sulfur reducer (Geobacter sulfurreducens) and Thiobacillus denitrificans was used to investigate that how organic carbon could boost the S0-based denitrification. The results showed that the rate of S0-based denitrification was improved with C/N ratio of 0.13 and this improvement continued even after the acetate was exhausted. Sulfur probe test and Raman analysis suggested that reduced sulfur species (Sx2-) were formed with the addition of organic carbon. The Sx2- could recombine with element sulfur and the bioavailability of S0 would be improved, as a result, the rate of S0-based denitrification increased as well. Nitrate reduction rate could further increase with the C/N ratio of 0.88, but it would decrease significantly when the C/N ratio increased to 1.50 as the high concentration of generated S2-. Our results provided explanations that why organic carbon addition would improve the bioavailability of S0 which could further promote the S0-dominant denitrification process.


Assuntos
Thiobacillus , Reatores Biológicos , Carbono , Desnitrificação , Geobacter , Nitratos , Nitrogênio , Enxofre
3.
Environ Pollut ; 267: 115447, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32866876

RESUMO

Properly increasing mobility of heavy metals could promote phytoremediation of contaminated soil. Fe1-xS/biochar was successfully prepared from sawdust with loading pyrrhotite (Fe1-xS) at a pyrolysis temperature of 550 °C. Thiobacillus were successfully adsorbed and enriched on the surface of Fe1-xS/biochar. Microbial growth for 36 d supported by bio-oxidization of Fe1-xS decreased the system pH from 4.32 to 3.50, increased the ORP from 298 to 487 mV, and the Fe3+ release reached 25.48 mg/g, enhancing the oxidation and leaching of soil Pb. Finally, Fe1-xS/biochar and Thiobacillus were simultaneously applied into Pb-contaminated soil for 60 d, the soil pH decreased from 7.83 to 6.72, and the exchangeable fraction of soil Pb increased from 22.86% to 37.19%. Ryegrass planting for 60 d in Pb-contaminated soil with Fe1-xS/biochar and Thiobacillus showed that the Pb content in shoot and root of ryegrass increased by 55.65% and 73.43%, respectively, confirming an obvious increase of phytoavailability of soil Pb. The relative abundance of Thiobacillus in remediated soil significantly increased from 0.06% to 34.55% due to the addition of Fe1-xS/biochar and Thiobacillus. This study provides a novel approach for regulating the Pb phytoavailability for phytoremediation of Pb-contaminated soil.


Assuntos
Metais Pesados , Poluentes do Solo , Thiobacillus , Carvão Vegetal , Solo , Poluentes do Solo/análise
4.
Chemosphere ; 258: 127146, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32531298

RESUMO

Tetramethylammonium hydroxide (TMAH) was often used as developer in the high-tech industries. Information regarding biological treatment of high TMAH-containing wastewater is limited. This study investigated aerobic degradation of high TMAH, its impacts on nitrification, and microbial community in a sequencing batch reactor (SBR). The initial TMAH concentrations of SBR gradually increased from 200 to 4666 mg L-1 (equivalent to 31 to 718 mg-N L-1) to enrich microbial community for aerobic TMAH degradation and nitrification. The results indicated that the aerobic specific TMAH degradation rates followed the Monod-type kinetics with a maximum specific TMAH degradation rate of 2.184 mg N hour-1 g volatile suspended solid (VSS)-1 and the half-saturation coefficient of 175.1 mg N L-1. After TMAH degradation and ammonia release, the lag time for the onset of nitrification highly correlated with initial TMAH fed for the SBR. According to the microbial community analysis using next generation sequencing (NGS), potential aerobic TMAH-degraders including Mycobacterium sp. and Hypomicrobium sp. were enriched in the aerobic SBR. The results of real-time quantitative polymerase chain reaction (qPCR) and reverse transcript (RT)-qPCR indicated that Hyphomicrobium sp. may be able to utilize both TMAH and its degradation intermediates such as trimethylamine (TMA), while Thiobacillus sp. can only utilize TMAH. The qPCR and RT-qPCR results suggested that TMAH may inhibit nitrification by inactive expression of amoA gene and the intermediates of TMAH degradation may compete ammonia monooxygenase (AMO) enzyme with ammonia for nitrification inhibition.


Assuntos
Microbiota/fisiologia , Compostos de Amônio Quaternário/metabolismo , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/metabolismo , Aerobiose , Amônia/metabolismo , Biodegradação Ambiental , Reatores Biológicos/microbiologia , Sequenciamento de Nucleotídeos em Larga Escala , Microbiota/genética , Mycobacterium/genética , Mycobacterium/metabolismo , Nitrificação , Compostos de Amônio Quaternário/química , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Thiobacillus/metabolismo , Eliminação de Resíduos Líquidos/instrumentação , Águas Residuárias/química , Poluentes Químicos da Água/química
5.
Sci Total Environ ; 713: 136698, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32019036

RESUMO

Bio-electrochemical denitrification (BED) is a promising organic carbon-free nitrate remediation technology. However, the relationship between engineering conditions, biofilm community composition, and resultant functions in BED remains under-explored. This study used deep sequencing and variation partitioning analysis to investigate the compositional shifts in biofilm communities under varied poised potentials in the batch mode, and correlated these shifts to reactor-level functional differences. Interestingly, the results suggest that the proliferation of a key species, Thiobacillus denitrificans, and community diversity (the Shannon index), were almost equally important in explaining the reactor-to-reactor functional variability (e.g. variability in denitrification rates was 51% and 38% attributable to key species and community diversity respectively, with a 30% overlap), but neither was heavily impacted by the poised potential. The findings suggest that while enriching the key species may be critical in improving the functional efficiency of BED, poised potentials may not be an effective strategy to achieve the desired level of enrichment in substrate-limited real-world conditions.


Assuntos
Desnitrificação , Biofilmes , Reatores Biológicos , Nitratos , Thiobacillus
6.
Water Res ; 172: 115501, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-31954933

RESUMO

Photoelectrotrophic denitrification (PEDeN) using bio-hybrids has the potential to remove nitrate (NO3-) from wastewater in an economical and sustainable way. As a gas of global concern, the mechanisms of nitrous oxide (N2O) emissions during this novel process remain unclear. Herein, a self-photosensitized bio-hybrid, i. e., Thiobacillus denitrificans-cadmium sulfide, was constructed and the factors affecting N2O emissions during PEDeN by the bio-hybrids were investigated. The system was sensitive to the input NO3--N and NO2--N, resulting in changes in the N2O/(N2+N2O) ratio from 1% to 95%. In addition to free nitrous acid (FNA), reactive oxidative species (ROS) were a unique factor affecting N2O emission during PEDeN. Importantly, the N2O reduction step exhibited greater susceptibility to the ROS than nitrate reduction step. The contributions of hydrogen peroxide (H2O2), superoxides (O2-•), hydroxyl radicals (•OH) and FNA to the inhibition of N2O reduction were >15.0%, >5.4%, 1.3%, and <70.2%, respectively for a reduction of 13.5 mg/L NO3--N. A significant down-regulation of the relative transcription of the gene nosZ demonstrated that the inhibition of N2O reductase occurred at the gene level. This finding has important implications not only for mitigating N2O emissions during the PEDeN process but also for encouraging a reexamination process of N2O emissions in nature, particularly in systems in which ROS are present during the denitrification process.


Assuntos
Desnitrificação , Thiobacillus , Peróxido de Hidrogênio , Nitratos , Óxido Nitroso
7.
Anim Sci J ; 91(1): e13313, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31755175

RESUMO

Ammonia removal is achieved partly by absorption and nitrification in biofilters, resulting in the accumulation of nitrogen and the necessity of treating the effluent water. We investigated the effects of thiosulfate addition to a biofilter containing pumice tuff for ammonia and nitrogen removal in a laboratory-scale experiment. The addition of thiosulfate to the circulating water led to a decreased nitrate and nitrite along with an increase of sulfate. The inorganic nitrogen in the circulating water decreased by up to 44% with thiosulfate addition compared to without thiosulfate. Batch experiments revealed that denitrification activity decreased exponentially along with increases in dissolved oxygen; however, approximately 30% of denitrification activity was maintained at dissolved oxygen concentration of 3.3 mg/L. Metabarcoding of 16S rRNA genes indicated that the genus Thiobacillus had a relative abundance of 0.002%-0.016% of total bacteria in the biofilter packing material. The circulating water pH was decreased below 5 with sulfur oxidation, and ammonium was accumulated without pH control resulting in a decrease in the relative abundance of the family Nitrosomonadaceae. Its relative abundance increased with control of pH to near neutral, indicating that ammonia-oxidizing activity could be maintained by adjusting pH. Thiosulfate addition could stimulate nitrogen removal by sulfur-dependent denitrification in biofiltration systems.


Assuntos
Filtros de Ar , Amônia , Desnitrificação , Nitrogênio , Silicatos , Tiossulfatos , Águas Residuárias , Concentração de Íons de Hidrogênio , Nitratos , Nitritos , Nitrosomonadaceae , RNA Ribossômico 16S , Thiobacillus
8.
Huan Jing Ke Xue ; 40(9): 4177-4184, 2019 Sep 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854883

RESUMO

The effects of Thiobacillus denitrificans combined with signal molecules on the removal of sulfide and nitrate was investigated. By adding signal molecules and T. denitrificans at the same, the total number of microorganisms increased, the removal of sulfide and nitrate was accelerated, and an increase in nitrogen gas and more stable accumulation of elemental sulfur was observed. The total number of microorganisms after the reaction was detected using fluorescence in situ hybridization (FISH) technique. In this experiment, the optimal concentration for the stable accumulation of elemental sulfur from six concentrations of signal molecules was revealed. Further, the effects of adding signal molecules, T. denitrificans, and their combination were analyzed at this concentration. The results showed that it was easier to accumulate elemental sulfur after the addition of 1.0 µmol·L-1 signal molecule. After adding both T. denitrificans and 1.0 µmol·L-1 signal molecules at a sulfide concentration of 200 mg·L-1, the removal of sulfide and nitrate increased to 99.8% and 96.9% at 72 h, respectively, and increases in nitrogen gas and sulfur were observed. The amounts of elemental sulfur and nitrogen gas reached to 59.0 mg and 80.0 mL, respectively, after adding 2.5 µmol·L-1 signal molecules at 72 h when the sulfide concentration was 300 mg·L-1. Under those conditions, the removal efficiency of sulfide and nitrate reached 99.0% and 93.9%, and the production of elemental sulfur and nitrogen reached 63.1 mg and 79.5 mL, respectively.


Assuntos
Nitrogênio , Enxofre , Thiobacillus , Reatores Biológicos , Hibridização in Situ Fluorescente , Nitratos , Nitrogênio/metabolismo , Sulfetos , Enxofre/metabolismo
9.
Sci Rep ; 9(1): 17870, 2019 11 28.
Artigo em Inglês | MEDLINE | ID: mdl-31780738

RESUMO

Engineered microbial ecosystems in biofilters have been widely applied to treat odorous gases from industrial emissions. Variations in microbial community structure and function associated with the removal of odorous gases by biofilters are largely unknown. This study performed a metagenomic analysis to discover shifts in microbial community structures in a commercial scale biofilter after treating odorous gas. Our study identified 175,675 functional genes assigned into 43 functional KEGG pathways. Based on the unigene sequences, there were significant changes in microbial community structures in the biofilter after treating odorous gas. The dominant genera were Thiobacillus and Oceanicaulis before the treatment, and were Acidithiobacillus and Ferroplasma after the treatment. A clustering analysis showed that the number of down-regulated microbes exceeded the number of up-regulated microbes, suggesting that odorous gas treatment reduced in microbial community structures. A differential expression analysis identified 29,975 up- and 452,599 down-regulated genes. An enrichment analysis showed 17 classic types of xenobiotic biodegradation pathways. The results identified 16 and 15 genes involved in ammonia and sulfite metabolism, respectively; an analysis of their relative abundance identified several up-regulated genes, which may be efficient genes involved in removing odorous gases. The data provided in this study demonstrate the changes in microbial communities and help identify the dominant microflora and genes that play key roles in treating odorous gases.


Assuntos
Poluentes Atmosféricos/metabolismo , Regulação Bacteriana da Expressão Gênica , Genes Bacterianos , Microbiota , Acidithiobacillus/genética , Acidithiobacillus/metabolismo , Biodegradação Ambiental , Variação Genética , Microbiologia Industrial/instrumentação , Microbiologia Industrial/métodos , Thiobacillus/genética , Thiobacillus/metabolismo , Xenobióticos/metabolismo
10.
Bioresour Technol ; 294: 122130, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31526933

RESUMO

A novel sulfide-based denitrification and Anammox process was established for simultaneous removal of nitrogen and sulfide in a UBF reactor. The effects of the N/S ratio on reactor performance were investigated under five N/S molar ratios (4.56, 2.38, 0.96, 0.73, and 0.51). The best total nitrogen removal efficiency was 82.8% at a N/S ratio of 2.38. When the N/S ratio exceeded 0.96, Anammox contributed to more than 90% of the N loss. Sulfide was completely removed during the full operational period and S0 accumulation occurred when N/S ratio was less than 1. Thiobacillus (6.1%) and Candidatus Kuenenia (18.8%) were the main functional microorganisms when nitrate was in excess on day 12. As nitrate became limited on day 50, Thiobacillus (21.0%), Sulfurimonas (3.9%), and Candidatus Kuenenia (19.7%) became dominated. In this study, Candidatus Kuenenia was not inhibited by the sulfide.


Assuntos
Microbiota , Thiobacillus , Reatores Biológicos , Desnitrificação , Nitrogênio , Oxirredução , Sulfetos
11.
Int. microbiol ; 22(3): 305-316, sept. 2019. ilus, graf, tab
Artigo em Inglês | IBECS | ID: ibc-184837

RESUMO

Effluents from petroleum refineries contain a toxic mixture of sulfide, nitrogen, and phenolic compounds that require adequate treatment for their removal. Biological denitrification processes are a cost-effective option for the treatment of these effluents, but the knowledge on the microbial interactions in simultaneous sulfide and phenol oxidation in denitrifying reactors is still very limited. In this work, microbial community structure and macrostructure of granular biomass were studied in three denitrifying reactors treating a mixture of inorganic (sulfide) and organic (p-cresol) electron donors for their simultaneous removal. The differences in the available substrates resulted in different community assemblies that supported high removal efficiencies, indicating the community adaptation capacity to the fluctuating compositions of industrial effluents. The three reactors were dominated by nitrate reducing and denitrifying bacteria where Thiobacillus spp. were the prevalent denitrifying organisms. The toxicity and lack of adequate substrates caused the endogenous decay of the biomass, leading to release of organic matter that maintained a diverse although not very abundant group of heterotrophs. The endogenous digestion of the granules caused the degradation of its macrostructure, which should be considered to further develop the denitrification process in sulfur-based granular reactors for treatment of industrial wastewater with toxic compounds


No disponible


Assuntos
Águas Residuárias/microbiologia , Desnitrificação , Microbiota , Sulfetos/metabolismo , Cresóis/química , Bactérias/metabolismo , Indústria de Petróleo e Gás , Ciclo do Nitrogênio , Sulfetos/química , Nitratos/química , Thiobacillus/isolamento & purificação , Biomassa
12.
Sci Total Environ ; 695: 133823, 2019 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-31421333

RESUMO

Sulfur autotrophic denitrification has been proved feasible for nitrate removal from aquatic environments and it utilizes elemental sulfur as the electron donor. A maximum denitrification rate of 194.57 mg N/L·d was achieved with biogenic sulfur as electron donor in a mixed culture collected from sulfur packed bed reactors; this rate was considerably higher than that delivered by α-S8 or µ-S in the same mixed culture. The elemental sulfur was also tested in the pure culture of Thiobacillus denitrificans, while a lower denitrification rate was noted than in the mixed culture, bio-S (4.86 mg N/L·d) again outperformed other two elemental sulfur's. X-ray absorption near edge structure spectra were collected to examine possible metabolic intermediates during the sulfur autotrophic denitrification process. The analysis revealed the existence of two major intermediates: DL-cysteine and L-cystine. They were found to not only provide electrons but also play a critical role in promoting the elemental sulfur-mediated sulfur autotrophic denitrification process. In general, we investigated the formation and enhancement effects of sulfur intermediates in the sulfur autotrophic denitrification process.


Assuntos
Biodegradação Ambiental , Desnitrificação/fisiologia , Nitrogênio/metabolismo , Processos Autotróficos , Cisteína , Cistina , Enxofre/metabolismo , Thiobacillus/metabolismo
13.
Sci Total Environ ; 682: 374-381, 2019 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-31125751

RESUMO

Anammox and autotrophic desulfurization-denitrification (AADD) process is feasible for the nitrogen and sulfide removal in the same reactor, and the influence of excess nitrate produced by anammox could also be alleviated simultaneously. This study firstly proposed a novel strategy with inoculating single anammox sludge to start up the AADD process. Results demonstrated that the 90% nitrogen removal efficiency (NRE), 2.55kgm-3 d-1 nitrogen removal rate (NRR), and 95% sulfide removal efficiency (SRE) were obtained at the influent total nitrogen of 280mgL-1 and sulfide of 221.5mgL-1, and the final effluent nitrate concentration was as low as 8mgL-1 under the appropriate operation conditions. Tryptophan-like and protein-like substances were characterized as the main components in bound EPS. Thiobacillus (35.68%) and Pseudoxanthomonas (11.61%) were identified as the predominant genera. This study will pave a potential avenue to promote the treatment of high concentration nitrogen and sulfide in wastewater in the future.


Assuntos
Eliminação de Resíduos Líquidos/métodos , Processos Autotróficos , Reatores Biológicos , Desnitrificação , Nitratos , Nitrogênio , Esgotos , Thiobacillus , Águas Residuárias
14.
J Hazard Mater ; 373: 359-366, 2019 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-30933858

RESUMO

With the short-term exposure to Fe2+, the mechanism of autotrophic denitrification and sulfide oxidation and the correlation between microbial community changes and environmental factors have been explored in the ADSOB process. RSM was used to optimize conditions for the maximum nitrate reduction and sulfide oxidation. About 88% of nitrate could be autotrophically denitrified to nitrogen by utilizing sulfide as the electron donor with the molar ratio C/N of 1.14 and S/N of 0.99 at pH 7.1. Lower Fe2+ additions can reduce TDS inhibition with dissolved sulfide to form FeS precipitates, while high amount of Fe2+ limited the mass transfer of NO3- and intermediate products such as S0 may be generated. High-throughput sequencing and RDA analysis revealed the correlation between ferrous iron, environmental factors and microorganisms. Sulfurospirillum, Rhodanobacter, Thauera and Thiobacillus were all slightly promoted at NFL level and inhibited at NFH level. And the narrow angles of the arrows indicated that Thauera, Sulfurospirillum and Thiobacillus were positively correlated with SO42- concentrations, while large angles indicated these bacteria were inversely related with TDS and NO3- arrows, which further confirmed that these bacteria played a dominant role in the ADSOB process, and can reduce NO3- by the oxidation of TDS. The correlation further indicated that lower Fe2+ additions have a promoting effect, while high concentrations have an inhibiting effect.


Assuntos
Desnitrificação , Ferro/administração & dosagem , Enxofre/metabolismo , Thauera/efeitos dos fármacos , Thiobacillus/efeitos dos fármacos , Processos Autotróficos , Nitratos/metabolismo , Oxirredução
15.
Environ Int ; 127: 353-360, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30954721

RESUMO

N2O (Nitrous oxide, a booster oxidant in rockets) has attracted increasing interest as a means of enhancing energy production, and it can be produced by nitrate (NO3-) reduction in NO3--loading wastewater. However, conventional denitrification processes are often limited by the lack of bioavailable electron donors. In this study, we innovatively propose a self-photosensitized nonphototrophic Thiobacillus denitrificans (T. denitrificans-CdS) that is capable of NO3- reduction and N2O production driven by light. The system converted >72.1 ±â€¯1.1% of the NO3--N input to N2ON, and the ratio of N2O-N in gaseous products was >96.4 ±â€¯0.4%. The relative transcript abundance of the genes encoding the denitrifying proteins in T. denitrificans-CdS after irradiation was significantly upregulated. The photoexcited electrons acted as the dominant electron sources for NO3- reduction by T. denitrificans-CdS. This study provides the first proof of concept for sustainable and low-cost autotrophic denitrification to generate N2O driven by light. The findings also have strong implications for sustainable environmental management because the sunlight-triggered denitrification reaction driven by nonphototrophic microorganisms may widely occur in nature, particularly in a semiconductive mineral-enriched aqueous environment.


Assuntos
Luz , Óxido Nitroso/metabolismo , Thiobacillus/fisiologia , Thiobacillus/efeitos da radiação , Processos Autotróficos , Desnitrificação , Nitratos/metabolismo
16.
J Environ Sci (China) ; 81: 214-224, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30975324

RESUMO

In order to reduce the amount of NO3--N generated by the Anammox process, and alleviate the competition between denitrification and Anammox for NO2--N in a single reactor, the preference of S0 for reacting with coexisting NO2--N and NO3--N in the sulfur autotrophic denitrifying (SADN) process and the coupling effect of short-cut SADN and the Anammox process were studied. The results showed that S0 preferentially reacted with NO3- to produce NO2--N, and then reacted with NO2--N when NO3--N was insufficient, which could effectively alleviate the competition between SADN bacteria (SADNB) and Anammox bacteria (AnAOB) for NO2--N. After 170 days of operation, coupling between short-cut S0-SADN and the Anammox process was first successfully achieved. SADNB converted the NO3--N generated by the Anammox process into NO2--N, which was once again available to AnAOB. The total nitrogen removal efficiency eventually stabilized at over 95%, and the effluent NO3--N was controlled within 10 mg/L, when high NH4+-N wastewater was treated by the Anammox process. Microbial community analysis further showed that Candidatus Brocadia and Thiobacillus were the functional microorganisms for AnAOB and SADNB.


Assuntos
Nitrogênio/análise , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/análise , Processos Autotróficos , Reatores Biológicos , Crescimento Quimioautotrófico , Desnitrificação/fisiologia , Nitratos , Nitrogênio/metabolismo , Thiobacillus , Águas Residuárias , Poluentes Químicos da Água/metabolismo
17.
Extremophiles ; 23(3): 283-304, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30778766

RESUMO

Geothermal plants are often affected by corrosion caused by microbial metabolites such as H2S. In the Bad Blumau (Austria) geothermal system, an increase in microbially produced H2S was observed in the hot (107 °C) and scaling inhibitor-amended saline fluids and in fluids that had cooled down (45 °C). Genetic fingerprinting and quantification revealed the dominance, increasing abundance and diversity of sulfate reducers such as Desulfotomaculum spp. that accompanied the cooling and processing of the geothermal fluids. In addition, a δ34S isotopic signature showed the microbial origin of the H2S that has been produced either chemolithotrophically or chemoorganotrophically. A nitrate addition test in a test pipe as a countermeasure against the microbial H2S formation caused a shift from a biocenosis dominated by bacteria of the phylum Firmicutes to a community of Firmicutes and Proteobacteria. Nitrate supported the growth of nitrate-reducing sulfur-oxidizing Thiobacillus thioparus, which incompletely reduced nitrate to nitrite. The addition of nitrate led to a change in the composition of the sulfate-reducing community. As a result, representatives of nitrate- and nitrite-reducing SRB, such as Desulfovibrio and Desulfonatronum, emerged as additional community members. The interaction of sulfate-reducing bacteria and nitrate-reducing sulfur-oxidizing bacteria (NR-SOB) led to the removal of H2S, but increased the corrosion rate in the test pipe.


Assuntos
Desulfovibrio , Firmicutes , Fontes Termais/microbiologia , Microbiota/fisiologia , Nitratos/metabolismo , Thiobacillus , Microbiologia da Água , Desulfovibrio/classificação , Desulfovibrio/crescimento & desenvolvimento , Firmicutes/citologia , Firmicutes/crescimento & desenvolvimento , Oxirredução , Thiobacillus/classificação , Thiobacillus/crescimento & desenvolvimento
18.
J Hazard Mater ; 368: 308-315, 2019 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-30685719

RESUMO

A potting experiment was conducted to investigate the effect of sulfur application on the bioaccumulation by tobacco and its mechanisms of rhizospheric microorganisms. Cadmium content in tobacco was analyzed using atomic absorption spectrometer, while bacterial community and related gene in soil were analyzed via high-throughput sequencing and quantitative PCR techniques, respectively. The obtained results indicated that tobacco had the ability to accumulate cadmium under no sulfur application conditions, with cadmium contents of 35.4, 23.6, and 26.3 mg kg-1 in leaves, stems, and roots, respectively. Under high-sulfur treatment, these values increased to 66.4, 46.1, and 42.6 mg kg-1, respectively, probably due to the increase of the available cadmium content (from 1.1 to 3.3 mg kg-1) in the soil through a decrease of the soil pH value, which was contributed by the sulfur oxidation reaction. dsrA and soxB genes might play an important role in sulfur oxidation, and Thiobacillus sp. was the dominant bacterial genus during the sulfur oxidation process. In addition, sulfur application exerted little effect on the diversity and structure of the soil bacterial community. The combined results indicate that sulfur application is an effective and safe method for Cd phytoextraction by tobacco.


Assuntos
Cádmio/metabolismo , Rizosfera , Microbiologia do Solo , Poluentes do Solo/metabolismo , Enxofre/farmacologia , Thiobacillus/efeitos dos fármacos , Tabaco/metabolismo , Bioacumulação , Biodegradação Ambiental , Cádmio/análise , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Solo/química , Poluentes do Solo/análise , Thiobacillus/isolamento & purificação , Tabaco/crescimento & desenvolvimento
19.
Waste Manag ; 80: 10-16, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30454988

RESUMO

Severe nitrogen (N) loss is a barrier for composting treatment. Since N transformation during composting is closely related to nitrogen loss, the impacts of adding sulphur and Thiobacillus thioparus 1904 to N transformation during composting were investigated in this work. Physicochemical properties and the expression of genes encoding N-related proteins were analysed to evaluate microbiological processes associated with N dynamics. The results indicated that (1) sulphur addition reduced the pH and cumulative NH3 emission, and decreased N losses by 44.23%, while no significant differences were observed in the expression of N cycle-associated genes compared with the control treatment; (2) the application of T. thioparus 1904 increased NO3--N content, reduced N loss by 28.20%, and significantly enhanced the expression of ammonia monooxygenase A (archaeal amoA; AOA) and nitrite oxidoreductase A (nxrA) during the mature phase; (3) the combined application of sulphur and T. thioparus 1904 significantly affected the expression of functional genes related to nitrification and denitrification, which contributed to a reduction in accumulated NH3 emission, an increase in NO4+-N content, and a decrease in N losses by 70.94%. Expression of ammonia monooxygenase A (bacterial amoA; AOB), nxrA and nitrous oxide reductase Z (nosZ) genes in the combined treatment was positively correlated with NO3--N, whereas expression of AOA and accumulation of NH3 were negatively correlated with NO3--N. These results indicate that the combined application of sulphur and T. thioparus 1904 had a significant regulatory effect on N cycle genes and effectively reduced the N loss during composting.


Assuntos
Compostagem , Thiobacillus , Animais , Galinhas , Esterco , Nitrogênio , Ciclo do Nitrogênio , Enxofre
20.
Mol Biol Rep ; 45(6): 1723-1731, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30443822

RESUMO

Thiobacillus, as useful soil bacteria, plays an important role in sulfur cycling. The purpose of this study was to identify the species Thiobacillus thioparus, Thiobacillus novellas and Thiobacillus denitrificans in rainfed and irrigated lands soil in Ajabshir, Ilam, Qorveh, Rojintaak, Sonqor, Kermanshah and Research Farm of Razi University in Iran. Sampling was performed as randomized completely with three replications at depth of 0-30 cm. The Thiobacillus species were determined via 16S rRNA characteristics. The results of agarose gel electrophoresis indicated that T. thioparus was the highest amount in the irrigated land in Research Farm and its lowest amount was in the Rojintaak rainfed land. These species not found in four locations and conditions including the Ajabshir irrigated, Qorveh rainfed, Research Farm rainfed and Rojintaak irrigated lands. The results of the T. novellas indicated that this was found in Ilam irrigated, Qorveh rainfed, Research Farm irrigated, Rojintaak irrigated and Rojintaak rainfed lands. The highest and lowest amount of T. novellas was indicated in the Rojintaak and Ilam irrigated lands respectively. The T. denitrificans gene showed that this bacterium was observed only in both samples of Ajabshir. Our study showed that Thiobacillus was not detected in all of the soils. If sulfur fertilizer is given to the soil without this bacterium, it is necessary to use sulfur fertilizer with Thiobacillus bacteria inoculation for better sulfur oxidation.


Assuntos
Microbiologia do Solo , Thiobacillus/genética , Thiobacillus/isolamento & purificação , Agricultura , Bactérias/genética , DNA Bacteriano/genética , Irã (Geográfico) , Filogenia , RNA Ribossômico 16S/genética , RNA Ribossômico 16S/isolamento & purificação , Solo , Enxofre/metabolismo , Thiobacillus/metabolismo
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