RESUMO
Sulfate-reducing bacteria (SRB) and a biochar array were used to reduce sulfate concentrations and the levels of metals in acid mine drainage (AMD) waters. Cow manure SRB-enriched biochar promoted sulfate reductions of 41% compared to original AMD, and 39% compared to other treatments (control, AMD sediment, sludge). Treatments reduced levels of all analyzed metals below Brazilian official standards. DGGE showed a significant relation between SRB-source and SRB-structural community, where cow manure and sludge presented the more cohesive community structure throughout the monitoring (180 days). The study showed that AMD treatment alternatives can be applied and are effective in reducing the contamination of wastewaters.
Assuntos
Carvão Vegetal/química , Desulfovibrio/metabolismo , Esterco/análise , Esgotos/microbiologia , Sulfatos/química , Purificação da Água/métodos , Ácidos/química , Animais , Brasil , Bovinos , Feminino , Metais/análise , Mineração/métodos , Aves DomésticasRESUMO
The intestinal microbiota is critical for mammalian immune system development and homeostasis. Sulfate-reducing bacteria (SRB) are part of the normal gut microbiota, but their increased levels may contribute to colitis development, likely in association with hydrogen sulfide (H2S) production. Here, we investigated the effects of SRB in the gut immune response in germ-free mice, and in experimental colitis. After 7days of colonization with Desulfovibrio indonesiensis or with a human SRB consortium (from patients with colitis), germ-free mice exhibited alterations in the colonic architecture, with increased cell infiltration in the lamina propria. SRB colonization upregulated the Th17 and Treg profiles of cytokine production/cell activation, in T cells from mesenteric lymph nodes. These alterations were more pronounced in mice colonized with the human SRB consortium, although D. indonesiensis colonization produced higher levels of H2S. Importantly, the colon of C57BL/6 mice with colitis induced by TNBS or oxazolone had increased SRB colonization, and the administration of D. indonesiensis to mice with TNBS-induced colitis clearly exacerbated the alterations in colonic architecture observed in the established disease, and also increased mouse weight loss. We conclude that SRB contribute to immune response activation in the gut and play an important role in colitis development.
Assuntos
Colite/patologia , Desulfovibrio/metabolismo , Inflamação/patologia , Sulfatos/metabolismo , Animais , Colite/imunologia , Modelos Animais de Doenças , Feminino , Humanos , Inflamação/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Oxazolona/toxicidade , Linfócitos T Reguladores/imunologia , Células Th17/imunologia , Ácido Trinitrobenzenossulfônico/toxicidade , Redução de PesoRESUMO
AIMS: The detection of trace concentrations of biogenic sulfides can be carried out through radiorespirometric assays. The objective of this work was to improve the methodology for detection of H2 S in trace concentrations, to correlate with sulfate-reducing bacterial activity. METHODS AND RESULTS: Serial dilutions of synthetic sea water with a pure culture of Desulfovibrio alaskensis, a mixed anaerobic microbial culture and a natural saline sample from a petroleum offshore platform indicated that dilutions were followed, accordingly, by sulfate reduction. CONCLUSIONS: Tests performed indicated that increasing the time of incubation of a mixed anaerobic microbial culture contributed to an increase in the sulfate reduction rates, as well as the amount of carbon source and inoculum. SIGNIFICANCE AND IMPACT OF THE STUDY: The technique here developed proved to be a rapid test for the detection of biogenic sulfides, particularly those associated with corrosion products, being an useful tool for monitoring and controlling oil/water storage tanks, petroleum continental platforms and several types of reservoirs.
Assuntos
Desulfovibrio/metabolismo , Água do Mar/microbiologia , Sulfetos/isolamento & purificação , Bactérias Redutoras de Enxofre/metabolismo , Carbono/metabolismo , Corrosão , Sulfatos/metabolismo , Microbiologia da ÁguaRESUMO
Volatile fatty acid (VFA) profile is an important parameter in anaerobic reactors because it enables the assessment of metabolic pathways. Volatile fatty acids were monitored during sulfate reduction in a UASB (upflow anaerobic sludge blanket) reactor treating 2g/L sulfate concentration and with the organic loading increasing from 3.5 kg COD/m(3)d to 5.9 kg COD/m(3)d, for a 1-day residence time. In the absence of recirculation, the best outcome (65% reduction) was noticed with the lowest organic loading (3.55 kg/m(3)d). When recirculation was applied, sulfate reduction yields increased to 89%, corresponding to a sulfate removal rate of 1.94 kg SO(4)(2-)/m(3)d. The reactor performance was discussed in relation to microbial diversity and metabolic pathways. At high organic loading, two metabolic pathways account for lactate degradation: (i) lactate is oxidized to acetate and carbon dioxide by the incomplete-oxidizer SRB (sulfate-reducing bacteria) Desulfomonas, Desulfovibrio, Desulfolobus, Desulfobulbus and Desulfotomaculum spp.; (ii) lactate is converted to acetate by fermenting bacteria such as Clostridium sp. High propionate concentrations imply that there are low sulfate reduction efficiencies.
Assuntos
Fermentação/fisiologia , Sulfatos/metabolismo , Reatores Biológicos/microbiologia , Desulfovibrio/metabolismo , Ácidos Graxos Voláteis/metabolismo , Ácido Láctico/metabolismo , Propionatos/metabolismoRESUMO
Two deltaproteobacterial sulfate reducers, designated strain I.8.1(T) and I.9.1(T), were isolated from the oxygen minimum zone water column off the coast of Peru at 400 and 500 m water depth. The strains were Gram-negative, vibrio-shaped and motile. Both strains were psychrotolerant, grew optimally at 20 degrees C at pH 7.0-8.0 and at 2.5-3.5% NaCl (w/v). The strains grew by utilizing hydrogen/acetate, C(3-4) fatty acids, amino acids and glycerol as electron acceptors for sulfate reduction. Fumarate, lactate and pyruvate supported fermentative growth. Sulfate, sulfite, thiosulfate and taurin supported growth as electron acceptors. Both strains were catalase-positive and highly oxygen-tolerant, surviving 24 days of exposure to atmospheric concentrations. MK6 was the only respiratory quinone. The most prominent cellular fatty acid was iso-17:1-omega9c (18%) for strain I.8.1(T) and iso-17:0-omega9c (14%) for strain I.9.1(T). The G+C contents of their genomic DNA were 45-46 mol%. Phylogenetic analysis of 16S rRNA and dsrAB gene sequences showed that both strains belong to the genus Desulfovibrio. Desulfovibrio acrylicus DSM 10141(T) and Desulfovibrio marinisediminis JCM 14577(T) represented their closest validly described relatives with pairwise 16S rRNA gene sequence identities of 98-99%. The level of DNA-DNA hybridization between strains I.8.1(T) and I.9.1(T) was 30-38%. The two strains shared 10-26% DNA-DNA relatedness with D. acrylicus. Based on a polyphasic investigation it is proposed that strains I.8.1(T) and I.9.1(T) represent a novel species for which the name Desulfovibrio oceani sp. nov. is proposed with the two subspecies D. oceani subsp. oceani (type strain, I.8.1(T) = DSM 21390(T) = JCM 15970(T)) and D. oceani subsp. galateae (type strain, I.9.1(T) = DSM 21391(T) = JCM 15971(T)).
Assuntos
Desulfovibrio/classificação , Desulfovibrio/metabolismo , Água do Mar/microbiologia , Sulfatos/metabolismo , Técnicas de Tipagem Bacteriana , Composição de Bases , Análise por Conglomerados , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Desulfovibrio/isolamento & purificação , Ácidos Graxos/análise , Concentração de Íons de Hidrogênio , Locomoção , Dados de Sequência Molecular , Hibridização de Ácido Nucleico , Oxirredução , Oceano Pacífico , Peru , Filogenia , Quinonas/análise , RNA Bacteriano/genética , RNA Ribossômico 16S/genética , RNA não Traduzido/genética , Análise de Sequência de DNA , Cloreto de Sódio/metabolismo , TemperaturaRESUMO
Integrated biological processes involving the dissolution and subsequent precipitation have been used for the treatment of the spent material from the hydrogenation of vegetable oil containing a high-level of nickel. Our results show that nickel was successfully leached using Acidithiobacillus thiooxidans. The percentages of nickel leached using A. thiooxidans were higher than those obtained with dilute sulphuric acid solutions. Due to the physical characteristics of the residue, the best results were obtained when the leaching process was carried out using sulphuric acid biogenerated by an A. thiooxidans biofilm. The recovery of nickel from the leachates was performed at room temperature by precipitating with sulphide generated by Desulfovibrio cells. Indirect precipitation using sulphide generated in Desulfovibrio sp. cultures allowed the recovery of nickel as the very insoluble nickel sulphide.
Assuntos
Acidithiobacillus thiooxidans/metabolismo , Desulfovibrio/metabolismo , Níquel/química , Óleos de Plantas , Ácidos Sulfúricos/química , Gerenciamento de Resíduos/métodos , Catálise , Precipitação Química , Indústria Alimentícia , Hidrogenação , Resíduos Industriais , Níquel/metabolismo , Ácidos Sulfúricos/metabolismoRESUMO
Desulfovibrio vulgaris subsp. oxamicus (type strain, DSM 1925(T)) was found to use nitrate as a terminal electron acceptor, the latter being reduced to ammonium. Phylogenetic studies indicated that strain DSM 1925(T) was distantly related to the type strain of Desulfovibrio vulgaris (95.4 % similarity of the small-subunit rRNA gene) and had as its closest phylogenetic relatives two other nitrate- and sulfate-reducing bacteria, namely Desulfovibrio termitidis (99.4 % similarity) and Desulfovibrio longreachensis (98.4 % similarity). Additional experiments were conducted to characterize better strain DSM 1925(T). This strain incompletely oxidized lactate and ethanol to acetate. It also oxidized butanol, pyruvate and citrate, but not glucose, fructose, acetate, propionate, butyrate, methanol, glycerol or peptone. The optimum temperature for growth was 37 degrees C (range 16-50 degrees C) and the optimum NaCl concentration for growth was 0.1 % (range 0-5 %). Because of significant genotypic and phenotypic differences from Desulfovibrio termitidis and Desulfovibrio longreachensis, reclassification of Desulfovibrio vulgaris subsp. oxamicus as Desulfovibrio oxamicus sp. nov., comb. nov., is proposed. The type strain is strain Monticello 2(T) (=DSM 1925(T)=NCIMB 9442(T)=ATCC 33405(T)).
Assuntos
Desulfovibrio vulgaris/classificação , Desulfovibrio/classificação , Nitratos/metabolismo , Sulfatos/metabolismo , Metabolismo dos Carboidratos , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Desulfovibrio/genética , Desulfovibrio/metabolismo , Desulfovibrio/fisiologia , Desulfovibrio vulgaris/genética , Desulfovibrio vulgaris/metabolismo , Desulfovibrio vulgaris/fisiologia , Genes de RNAr/genética , Inibidores do Crescimento/farmacologia , Dados de Sequência Molecular , Oxirredução , Peptonas/metabolismo , Filogenia , Compostos de Amônio Quaternário/metabolismo , RNA Bacteriano/genética , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Homologia de Sequência do Ácido Nucleico , Cloreto de Sódio/farmacologiaRESUMO
A novel halotolerant sulfate-reducing bacterium, Desulfovibrio brasiliensis strain LVform1, was isolated from sediments of a dolomite-forming hypersaline coastal lagoon, Lagoa Vermelha, in the state of Rio de Janeiro, Brazil. The cells are vibrio-shaped and 0.30 to 0.45 microm by 1.0 to 3.5 microm in size. These bacteria mediate the precipitation of dolomite [CaMg(CO3)2] in culture experiments. The strain was identified as a member of the genus Desulfovibrio in the delta-subclass of the Proteobacteria on the basis of its 16S rRNA gene sequence, its physiological and morphological properties. Strain LVform1 is obligate sodium-dependent and grows at NaCl concentrations of up to 15%. The 16S rRNA sequence revealed that this strain is closely related to Desulfovibrio halophilus (96.2% similarity) and to Desulfovibrio oxyclinae (96.8% similarity), which were both isolated from Solar Lake, a hypersaline coastal lake in the Sinai, Egypt. Strain LVform1 is barotolerant, growing under pressures of up to 370 bar (37 MPa). We propose strain LVform1 to be the type strain of a novel species of the genus Desulfovibrio, Desulfovibrio brasiliensis (type strain LVform1 = DSMZ No. 15816 and JCM No. 12178). The GenBank/EMBL accession number for the 16S rDNA sequence of strain LVform1 is AJ544687.
Assuntos
Carbonato de Cálcio , Desulfovibrio/metabolismo , Magnésio , Sulfatos/metabolismo , Brasil , Desulfovibrio/genética , Desulfovibrio/ultraestrutura , Temperatura Alta , Magnésio/metabolismo , Microscopia Eletrônica de Varredura , Oxirredução , RNA Bacteriano/genética , RNA Ribossômico 16S/genéticaRESUMO
Bacterial taxonomy using mathematical methods can be carried out with different techniques. Two techniques are used in this paper: analysis of principal coordinates and factor analysis of correspondences. The first one allows 2 and 3 dimension graphs of bacteria, thus showing their relationship considering proximity. The second one gives new data because it is an analysis which allows to connect bacteria to the reactions which identify them. In order to carry out these analyses 14 strains of the Desulfovibrio genus were studied, thus obtaining a classification consistent with other numeric method (group analysis with Simple Matching coefficient of average bond) to which it adds new information.
Assuntos
Desulfovibrio/classificação , Técnicas de Tipagem Bacteriana/estatística & dados numéricos , Classificação/métodos , Apresentação de Dados , Desulfovibrio/metabolismo , Análise Fatorial , Análise Multivariada , Especificidade da EspécieRESUMO
The Desulfovibrio genus has a particular interest because it includes the microorganisms connected with the corrosion produced microbiologically. The taxonomy of the genus shows disadvantages due to its metabolical and physiological characteristics. In this paper, 14 strains of the Desulfovibrio type were studied from the metabolical point of view. Numeric taxonomy was carried out according to the Group Analysis method, using and comparing the change possibilities of the method. The Consensus Method was also applied. The results obtained indicate a low metabolic activity of the strains with regard to the number of compounds which can be used as energy source. The taxonomic method showed a better structure with more clear divisions, corresponding to Simple Matching coefficient (which coincides with other symmetric coefficients and with the distance coefficient) with average bond (UPGMA). It is estimated that the present classification will vary in time with new strains with different metabolic characteristics. The two groups of bacteria correspond to those with more and less degrading ability.