Topic
Microbial consortium
About: Microbial consortium is a research topic. Over the lifetime, 1166 publications have been published within this topic receiving 29518 citations. The topic is also known as: Bacterial community & Consorm.
Papers published on a yearly basis
Papers
More filters
TL;DR: Enrichment by repeated transfer of a bacterial consortium harvested from the anode compartment of a biofuel cell in which glucose was used increased the output and selected organisms capable of mediating the electron transfer either by direct bacterial transfer or by excretion of redox components.
Abstract: Microbial fuel cells hold great promise as a sustainable biotechnological solution to future energy needs. Current efforts to improve the efficiency of such fuel cells are limited by the lack of knowledge about the microbial ecology of these systems. The purposes of this study were (i) to elucidate whether a bacterial community, either suspended or attached to an electrode, can evolve in a microbial fuel cell to bring about higher power output, and (ii) to identify species responsible for the electricity generation. Enrichment by repeated transfer of a bacterial consortium harvested from the anode compartment of a biofuel cell in which glucose was used increased the output from an initial level of 0.6 W m−2 of electrode surface to a maximal level of 4.31 W m−2 (664 mV, 30.9 mA) when plain graphite electrodes were used. This result was obtained with an average loading rate of 1 g of glucose liter−1 day−1 and corresponded to 81% efficiency for electron transfer from glucose to electricity. Cyclic voltammetry indicated that the enhanced microbial consortium had either membrane-bound or excreted redox components that were not initially detected in the community. Dominant species of the enhanced culture were identified by denaturing gradient gel electrophoresis and culturing. The community consisted mainly of facultative anaerobic bacteria, such as Alcaligenes faecalis and Enterococcus gallinarum, which are capable of hydrogen production. Pseudomonas aeruginosa and other Pseudomonas species were also isolated. For several isolates, electrochemical activity was mainly due to excreted redox mediators, and one of these mediators, pyocyanin produced by P. aeruginosa, could be characterized. Overall, the enrichment procedure, irrespective of whether only attached or suspended bacteria were examined, selected for organisms capable of mediating the electron transfer either by direct bacterial transfer or by excretion of redox components.
1,234 citations
TL;DR: It is shown that the direct, anaerobic oxidation of methane coupled to denitrification of nitrate is possible and that the reaction presented here may make a substantial contribution to biological methane and nitrogen cycles.
Abstract: Modern agriculture has accelerated biological methane and nitrogen cycling on a global scale. Freshwater sediments often receive increased downward fluxes of nitrate from agricultural runoff and upward fluxes of methane generated by anaerobic decomposition. In theory, prokaryotes should be capable of using nitrate to oxidize methane anaerobically, but such organisms have neither been observed in nature nor isolated in the laboratory. Microbial oxidation of methane is thus believed to proceed only with oxygen or sulphate. Here we show that the direct, anaerobic oxidation of methane coupled to denitrification of nitrate is possible. A microbial consortium, enriched from anoxic sediments, oxidized methane to carbon dioxide coupled to denitrification in the complete absence of oxygen. This consortium consisted of two microorganisms, a bacterium representing a phylum without any cultured species and an archaeon distantly related to marine methanotrophic Archaea. The detection of relatives of these prokaryotes in different freshwater ecosystems worldwide indicates that the reaction presented here may make a substantial contribution to biological methane and nitrogen cycles.
1,171 citations
TL;DR: Property of feed that place constraints on microbial attachment and biofilm formation can have a profound effect on both the rate and extent of feed digestion in the rumen, and developments in feed processing, plant breeding, and genetic engineering that overcome these constraints could substantially benefit ruminant production.
Abstract: Direct microscopic examination of the rumen and its contents shows microbial populations largely attached to feed particles in the digesta Most feeds contain a surface layer that is resistant to attachment and therefore to digestion Infiltration of these recalcitrant epidermal layers through damage sites or through focused enzymatic attack is essential for initiation of the digestive process Proliferation of primary colonizing cells produces glycocalyx-enclosed microcolonies Secondary colonizers from the ruminal fluid associate with microcolonies, resulting in the formation of multispecies microbial biofilms These metabolically related organisms associate with their preferred substrates and produce the myriad of enzymes necessary for the digestion of chemically and structurally complex plant tissues Upon accessing the internal, enzyme-susceptible tissues, microbial "digestive consortia" attach to a variety of nutrients, including protein, cellulose, and starch and digest insoluble feed materials from the inside out Substances that prevent microbial attachment or promote detachment (eg, condensed tannins, methylcellulose) can completely inhibit cellulose digestion As the microbial consortium matures and adapts to a particular type of feed, it becomes inherently stable and its participant microorganisms are notoriously difficult to manipulate due to the impenetrable nature of biofilms Properties of feed that place constraints on microbial attachment and biofilm formation can have a profound effect on both the rate and extent of feed digestion in the rumen Developments in feed processing (ie, chemical and physical), plant breeding, and genetic engineering (both of ruminal microorganisms and plants) that overcome these constraints through the promotion of microbial attachment and biofilm formation could substantially benefit ruminant production
562 citations
TL;DR: Bacterial strains used in this study were from the Center for Research in Enzymes and Microbiology (CREAM) collection of strains, at Universiti Putra Malaysia, and were isolated from hydrocarbon-contaminated soil samples by enrichments on either crude oil or individual hydrocarbons as the sole carbon source.
501 citations
TL;DR: It is demonstrated that an electricity-generating microbial consortium can be enriched using a fuel cell and that the electrochemical activity is a form of anaerobic electron transfer.
Abstract: A fuel cell was used to enrich a microbial consortium generating electricity, using organic wastewater as the fuel. Within 30 days of enrichment the maximum current of 0.2 mA was generated with a resistance of 1 kΩ. Current generation was coupled to a fall in chemical oxygen demand from over 1,700 mg l−1 down to 50 mg l−1. Denaturing gradient gel electrophoresis showed a different microbial population in the enriched electrode from that in the sludge used as the inoculum. Electron microscopic observation showed a biofilm on the electrode surface and microbial clumps. Nanobacteria-like particles were present on the biofilm surface. Metabolic inhibitors and electron acceptors inhibited the current generation. 16S ribosomal RNA gene analysis showed a diverse bacterial population in the enrichment culture. These findings demonstrate that an electricity-generating microbial consortium can be enriched using a fuel cell and that the electrochemical activity is a form of anaerobic electron transfer.
461 citations