scholarly journals Hydrogen production bySulfurospirillumspp. enables syntrophic interactions of Epsilonproteobacteria

2017 ◽  
Author(s):  
Stefan Kruse ◽  
Tobias Goris ◽  
Martin Westermann ◽  
Lorenz Adrian ◽  
Gabriele Diekert

AbstractHydrogen-producing bacteria are of environmental and biotechnological importance in anoxic environments, since hydrogen is an important electron donor for prokaryotes and of interest as an alternative energy source. Epsilonproteobacteria, inhabiting ecologically, clinically or biotechnologically relevant environments, are currently considered to be hydrogen-oxidizing bacteria exclusively. Here, we report hydrogen production for a genus of free-living Epsilonproteobacteria,Sulfurospirillumspp. inhabiting sediments, wastewater plants, bioelectrodes, oil reservoirs, contaminated areas, or marine habitats. The amount of hydrogen production was largely different in two subgroups ofSulfurospirillumspp., represented byS. cavoleiandS. multivorans. The former is shown to be the more potent hydrogen producer and excretes acetate as sole organic acid, while the latter exhibited a more flexible fermentation, producing additionally lactate and succinate. The observed hydrogen production could be assigned to a group 4 hydrogenase similar to Hydrogenase 4 (Hyf) inE. coli. We propose thatSulfurospirillumspp. produce molecular hydrogen with electrons derived from pyruvate oxidation by pyruvate:ferredoxin oxidoreductase and reduced ferredoxin. This hypothesis is supported by comparative proteome data, in which both PFOR and ferredoxin as well as hydrogenase 4 are up-regulated. A co-culture experiment withS. multivoransandMethanococcus voltaecultivated with lactate as sole substrate shows a syntrophic interaction between both organisms, since the former cannot grow fermentatively on lactate alone and the latter relies on hydrogen as electron donor. This opens up new perspectives on microbial communities, since Epsilonproteobacteria could play a yet unrecognized role as hydrogen producers in anoxic microbial communities.


Author(s):  
Reza Ziazi ◽  
Kasra Mohammadi ◽  
Navid Goudarzi

Hydrogen as a clean alternative energy carrier for the future is required to be produced through environmentally friendly approaches. Use of renewables such as wind energy for hydrogen production is an appealing way to securely sustain the worldwide trade energy systems. In this approach, wind turbines provide the electricity required for the electrolysis process to split the water into hydrogen and oxygen. The generated hydrogen can then be stored and utilized later for electricity generation via either a fuel cell or an internal combustion engine that turn a generator. In this study, techno-economic evaluation of hydrogen production by electrolysis using wind power investigated in a windy location, named Binaloud, located in north-east of Iran. Development of different large scale wind turbines with different rated capacity is evaluated in all selected locations. Moreover, different capacities of electrolytic for large scale hydrogen production is evaluated. Hydrogen production through wind energy can reduce the usage of unsustainable, financially unstable, and polluting fossil fuels that are becoming a major issue in large cities of Iran.



Author(s):  
D. Enyidi Uchechukwu ◽  
M. T. Okoli

The microbial communities of culture water and catfish C. gariepinus from three replicates of earthen, concrete and tarpaulin ponds in Nigeria were analyzed. Waters was collected from 25 cm below pond water surface per culture system. Three catfish per replicate system were also collected and analyzed in the lab. Catfish gut, skin and gills were analyzed. Earthen ponds had significantly more diverse microbial community and coliform forming units (CFU/ml) 2.43 x10-4 CFU/ml than the rest systems. Earthen ponds had consortium of Klebsiella pneumonia, S. aureus and Salmonella enteritidis and E. coli, which was more diverse than all other aquaculture systems.  Microbiota of tarpaulin ponds was 2.10x10-4 /ml CFU and this was significantly (P<0.05) higher than concrete ponds (1.50x10-4 CFU/ml). Tarpaulin ponds had K. pneumoniae and E. coli, while concrete pond had S. aureus and S. enteritidis. Biofilm formation could have lead to colonization of the fish body part. The skin and gills had similar microbiota as the culture water compared to the gut. The gut microbial communities were not synonymous with the culture water.



2010 ◽  
Vol 35 (16) ◽  
pp. 8371-8384 ◽  
Author(s):  
Jeffrey R. Bartels ◽  
Michael B. Pate ◽  
Norman K. Olson


2020 ◽  
Vol 8 ◽  
Author(s):  
Wenjuan Han ◽  
Minhan Li ◽  
Yuanyuan Ma ◽  
Jianping Yang

Hydrogen has been considered as a promising alternative energy to replace fossil fuels. Electrochemical water splitting, as a green and renewable method for hydrogen production, has been drawing more and more attention. In order to improve hydrogen production efficiency and lower energy consumption, efficient catalysts are required to drive the hydrogen evolution reaction (HER). Cobalt (Co)-based metal-organic frameworks (MOFs) are porous materials with tunable structure, adjustable pores and large specific surface areas, which has attracted great attention in the field of electrocatalysis. In this review, we focus on the recent progress of Co-based metal-organic frameworks and their derivatives, including their compositions, morphologies, architectures and electrochemical performances. The challenges and development prospects related to Co-based metal-organic frameworks as HER electrocatalysts are also discussed, which might provide some insight in electrochemical water splitting for future development.



mSystems ◽  
2019 ◽  
Vol 4 (6) ◽  
Author(s):  
Emilia M. Sogin ◽  
Erik Puskás ◽  
Nicole Dubilier ◽  
Manuel Liebeke

ABSTRACT Microbial communities exchange molecules with their environment, which plays a major role in regulating global biogeochemical cycles and climate. While extracellular metabolites are commonly measured in terrestrial and limnic ecosystems, the presence of salt in marine habitats limits the nontargeted analyses of the ocean exometabolome using mass spectrometry (MS). Current methods require salt removal prior to sample measurements, which can alter the molecular composition of the metabolome and limit the types of compounds detected by MS. To overcome these limitations, we developed a gas chromatography MS (GC-MS) method that avoids sample altering during salt removal and that detects metabolites down to nanomolar concentrations from less than 1 ml of seawater. We applied our method (SeaMet) to explore marine metabolomes in vitro and in vivo. First, we measured the production and consumption of metabolites during the culture of a heterotrophic bacterium, Marinobacter adhaerens. Our approach revealed successional uptake of amino acids, while sugars were not consumed. These results show that exocellular metabolomics provides insights into nutrient uptake and energy conservation in marine microorganisms. We also applied SeaMet to explore the in situ metabolome of coral reef and mangrove sediment porewaters. Despite the fact that these ecosystems occur in nutrient-poor waters, we uncovered high concentrations of sugars and fatty acids, compounds predicted to play a key role for the abundant and diverse microbial communities in coral reef and mangrove sediments. Our data demonstrate that SeaMet advances marine metabolomics by enabling a nontargeted and quantitative analysis of marine metabolites, thus providing new insights into nutrient cycles in the oceans. IMPORTANCE Nontargeted approaches using metabolomics to analyze metabolites that occur in the oceans is less developed than those for terrestrial and limnic ecosystems. One of the challenges in marine metabolomics is that salt limits metabolite analysis in seawater to methods requiring salt removal. Building on previous sample preparation methods for metabolomics, we developed SeaMet, which overcomes the limitations of salt on metabolite detection. Considering that the oceans contain the largest dissolved organic matter pool on Earth, describing the marine metabolome using nontargeted approaches is critical for understanding the drivers behind element cycles, biotic interactions, ecosystem function, and atmospheric CO2 storage. Our method complements both targeted marine metabolomic investigations as well as other “omics” (e.g., genomics, transcriptomics, and proteomics) approaches by providing an avenue for studying the chemical interaction between marine microbes and their habitats.



2012 ◽  
Vol 81 (3) ◽  
pp. 838-849 ◽  
Author(s):  
Francis Dziva ◽  
Heidi Hauser ◽  
Thomas R. Connor ◽  
Pauline M. van Diemen ◽  
Graham Prescott ◽  
...  

ABSTRACTAvian pathogenicEscherichia coli(APEC) causes respiratory and systemic disease in poultry. Sequencing of a multilocus sequence type 95 (ST95) serogroup O1 strain previously indicated that APEC resemblesE. colicausing extraintestinal human diseases. We sequenced the genomes of two strains of another dominant APEC lineage (ST23 serogroup O78 strains χ7122 and IMT2125) and compared them to each other and to the reannotated APEC O1 sequence. For comparison, we also sequenced a human enterotoxigenicE. coli(ETEC) strain of the same ST23 serogroup O78 lineage. Phylogenetic analysis indicated that the APEC O78 strains were more closely related to human ST23 ETEC than to APEC O1, indicating that separation of pathotypes on the basis of their extraintestinal or diarrheagenic nature is not supported by their phylogeny. The accessory genome of APEC ST23 strains exhibited limited conservation of APEC O1 genomic islands and a distinct repertoire of virulence-associated loci. In light of this diversity, we surveyed the phenotype of 2,185 signature-tagged transposon mutants of χ7122 following intra-air sac inoculation of turkeys. This procedure identified novel APEC ST23 genes that play strain- and tissue-specific roles during infection. For example, genes mediating group 4 capsule synthesis were required for the virulence of χ7122 and were conserved in IMT2125 but absent from APEC O1. Our data reveal the genetic diversity ofE. colistrains adapted to cause the same avian disease and indicate that the core genome of the ST23 lineage serves as a chassis for the evolution ofE. colistrains adapted to cause avian or human disease via acquisition of distinct virulence genes.



2015 ◽  
Vol 40 (12) ◽  
pp. 4329-4336 ◽  
Author(s):  
Peng Zhou ◽  
Yiming Wang ◽  
Rui Gao ◽  
Jin Tong ◽  
Zhengyu Yang


2014 ◽  
Vol 13 (1) ◽  
Author(s):  
Bartosz Hrycak ◽  
Dariusz Czylkowski ◽  
Robert Miotk ◽  
Miroslaw Dors ◽  
Mariusz Jasinski ◽  
...  

AbstractHydrogen seems to be one of the most promising alternative energy sources. It is a renewable fuel as it could be produced from e.g. waste or bio-ethanol. Furthermore hydrogen is compatible with fuel cells and is environmentally clean. In contrast to conventional methods of hydrogen production such as water electrolysis or coal gasification we propose a method based on atmospheric pressure microwave plasma. In this paper we present results of the experimental investigations of hydrogen production from ethanol in the atmospheric pressure plasma generated in waveguide-supplied cylindrical type nozzleless microwave (2.45 GHz) plasma source (MPS). Nitrogen was used as a working gas. All experimental tests were performed with the nitrogen flow rate Q ranged from 1500 to 3900 NL h





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