Search results for "Geobacter"
showing 10 items of 14 documents
Granulation and microbial community dynamics in the chitosan-supplemented anaerobic treatment of wastewater polluted with organic solvents.
2018
Abstract The effect of chitosan on the development of granular sludge in upflow anaerobic sludge blanket reactors (UASB) when treating wastewater polluted with the organic solvents ethanol, ethyl acetate, and 1-ethoxy-2-propanol was evaluated. Three UASB reactors were operated for 219 days at ambient temperature with an organic loading rate (OLR) of between 0.3 kg COD m −3 d −1 and 20 kg COD m −3 d −1 . One reactor was operated without the addition of chitosan, while the other two were operated with the addition of chitosan doses of 2.4 mg gVSS −1 two times. The three reactors were all able to treat the OLR tested with COD removal efficiencies greater than 90%. However, the time required to…
Interspecies interactions mediated by conductive minerals in the sediments of the iron rich meromictic Lake La Cruz, Spain
2019
espanolLa laguna de La Cruz puede considerarse como un analogo biogeoquimico de los ambientes marinos en la Tierra primitiva, porque su columna de agua, muy escasa en sulfato pero rica en metano y hierro, presenta condiciones similares a estos ambientes en el Precambrico. En este ambiente encontramos que particulas conductivas establecen un acoplamiento metabolico entre clados microbianos electroactivos. Demostraremos que el sedimento anoxico de la laguna de La Cruz, rico en minerales de hierro biogeoquimicamente “reactivos”, alberga conocidas especies electroactivas tales como Geobacter y Methanothrix, ademas de otros grupos microbianos que no han sido previamente asociados con un estilo d…
Control of VOCs from printing press air emissions by anaerobic bioscrubber: Performance and microbial community of an on-site pilot unit
2017
Abstract A novel process consisted of an anaerobic bioscrubber was studied at the field scale for the removal of volatile organic compounds (VOCs) emitted from a printing press facility. The pilot unit worked under high fluctuating waste gas emissions containing ethanol, ethyl acetate, and 1-ethoxy-2-propanol as main pollutants, with airflows ranging between 184 and 1253 m 3 h −1 and an average concentration of 1126 ± 470 mg-C Nm −3 . Three scrubber configurations (cross-flow and vertical-flow packings and spray tower) were tested, and cross-flow packing was found to be the best one. For this packing, daily average values of VOC removal efficiency ranged between 83% and 93% for liquid to a…
Strong regionality and dominance of anaerobic bacterial taxa characterize diazotrophic bacterial communities of the arcto-alpine plant species Oxyria…
2017
Arctic and alpine biomes are most often strongly nitrogen-limited, and hence biological nitrogen fixation is a strong driver of these ecosystems. Both biomes are characterized by low temperatures and short growing seasons, but they differ in seasonality of solar radiation and in soil water balance due to underlying permafrost in the Arctic. Arcto-alpine plant species are well-adapted to the low temperatures that prevail in their habitats, and plant growth is mainly limited by the availability of nutrients, in particular nitrogen, due to slow mineralization. Nitrogen fixing bacteria are likely important for plant growth in these habitats, but very little is known of these bacteria or forces …
Effect of substrate composition on the stability and microbial community of an anaerobic expanded granular sludge bed reactor treating printing solve…
2019
Abstract The performance and microbial community analysis of an expanded granular sludge bed reactor (EGSB) treating wastewater polluted with mixtures of ethanol and glycol ethers –such as 1-ethoxy-2-propanol (E2P) and 1-methoxy-2-propanol (M2P)– were evaluated. The results showed good EGSB performance during start-up (100% of ethanol) in terms of global removal efficiency (RE > 95%). When glycol ethers were added, an initial adaptation period was observed of ~20 days. While the RE of M2P became complete, the RE of E2P reached only 65%. The proportion of glycol ethers was gradually increased and at the end of this study only a binary mixture of E2P and M2P was fed. In the last stage, the gl…
Interspecies interactions mediated by conductive minerals in the sediments of the ferruginous Lake La Cruz, Spain
2018
AbstractLake La Cruz is considered a biogeochemical analogue to early Earth marine environments because its water column is depleted in sulfate, but rich in methane and iron, similar to conditions envisaged for much of the Precambrian. In this early Earth analogue environment, we show that conductive particles establish a tight metabolic coupling between electroactive microbial clades. We propose that mineral-based syntrophy is of potential relevance for the evolution of Earth’s earliest complex life forms. We show that the anoxic sediment of Lake La Cruz, which is rich in biogeochemically ‘reactive’ iron minerals, harbors known electroactive species such asGeobacterandMethanothrix,in addit…
Genetic methods to improve Cr(VI) bioremediation in groundwater
2009
Cr(VI) contamination of groundwater and soils is a primary public health. Bioremediation is an environmental-friendly alternative for Cr(VI) removal from groundwater and soils, but Cr(VI) toxicity limits the efficiency of the process. We use the genome shuffling technique in order to improve Cr(VI) tolerance and Cr(VI) reduction capability of the strict anaerobic bacterium Geobacter metallireducens. We will investigate the mechanism of Cr(VI) reduction in the resulting G. metallireducens mutants through an innovative electrochemical approach. Finally, we will test the best performing mutants in a bench-scale Cr(VI) bioremediation process.
GEOBACTER METALLIREDUCENS MUTANTS FOR CHROMIUM BIOREMEDIATION
2011
Genetic technology to improve biofilms electroactivity for bioremediation applications
Genetic technology to improve biofilms electroactivity for bioremediation applications
2010
Hexavalent chromium bioremediation occurs through its reduction to Cr(III) and its following precipitation. Geobacter metallireducens is a dissimilatory metal reducing bacteria known to reduce Cr(VI) to Cr(III) through extracellular electron transfer. However, the effectiveness of this bioreduction process is limited by the low toxicity resistance of G. metallireducens to Cr(VI). G. metallireducens mutants with improved Cr(VI) toxicity resistance can be obtained by genome shuffling method. Here we present the experimental setup for genome shuffling of G. metallireducens, including the optimization of mutagenesis procedure and the respiration rate measure for G. metallireducens in potentiost…
Start-Up of Chitosan-Assisted Anaerobic Sludge Bed Reactors Treating Light Oxygenated Solvents under Intermittent Operation
2021
Quality of the granular sludge developed during the start-up of anaerobic up-flow sludge bed reactors is of crucial importance to ensure the process feasibility of treating industrial wastewater such as those containing solvents. In this study, the microbial granule formation from suspended-growth biomass was investigated in two chitosan-assisted reactors. These reactors operated mimicking industrial sites working with night closures treating a mixture of ethanol, ethyl acetate, and 1-ethoxy-2-propanol. Each reactor operated under different hydrodynamic regimes typical from UASB (R1: <