Author
Juliana Calábria de Araújo
Other affiliations: Swiss Federal Institute of Aquatic Science and Technology, Federal University of Pará, Federal Fluminense University ...read more
Bio: Juliana Calábria de Araújo is an academic researcher from Universidade Federal de Minas Gerais. The author has contributed to research in topics: Anammox & Sequencing batch reactor. The author has an hindex of 18, co-authored 61 publications receiving 1281 citations. Previous affiliations of Juliana Calábria de Araújo include Swiss Federal Institute of Aquatic Science and Technology & Federal University of Pará.
Topics: Anammox, Sequencing batch reactor, Effluent, Population, Sewage
Papers published on a yearly basis
Papers
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TL;DR: A fast procedure for scanning electron microscopy (SEM) analysis in which hexamethyldisilazane (HMDS) solvent is used to remove liquids from a microbiological specimen and does not cause cell structure disruption.
Abstract: We present a fast procedure for scanning electron microscopy (SEM) analysis in which hexamethyldisilazane (HMDS) solvent, instead of the critical point drying, is used to remove liquids from a microbiological specimen. The results indicate that the HMDS solvent is suitable for drying samples of anaerobic cells for examination by SEM and does not cause cell structure disruption.
186 citations
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TL;DR: Results underline the differential sensitivity of these tasks to assess serotonergic agents; alternatively, serotonin might regulate zebrafish behavior differently in the novel tank test and in the light/dark test.
155 citations
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22 Mar 2017TL;DR: This study presents a review of the microbial diversity studies in anammox reactors, and finds that some microbial groups such as Proteobacteria and Chloroflexi have always been found with Planctomycetes in anlammox reactors.
Abstract: The anammox (anaerobic ammonium oxidation) process has been used to remove nitrogen from wastewaters and is considered a promising approach due to its advantages over conventional processes (nitrification and denitrification). The development of molecular biology tools has allowed for great advances in describing the microbial communities in anammox reactors, which is important to understand the complex reactions and interactions that occur inside these systems. This study presents a review of the microbial diversity studies in anammox reactors. Several researchers have investigated the microbial community composition in anammox reactors, in order to elucidate the roles that the different microbial groups (besides the anammox bacteria) play in these systems. The microbial communities of anammox reactors appear to be affected by several factors, such as the configuration of the reactors, the biomass growth mode inside of the reactors, operational conditions and type of inoculum used for start-up. H...
116 citations
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TL;DR: The results indicate that phenol adversely affects anammox metabolism and changes the bacterial community within theAnammox reactor.
100 citations
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TL;DR: The possibility of using the anammox process to remove nitrogen from anaerobically pre-treated municipal wastewater was demonstrated and DGGE revealed that the addition of anaerobic effluent changed the bacterial community structure and selected for DNA sequences related to Brocadia sinica and Chloroflexi.
87 citations
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TL;DR: The results presented here suggest that microbiological catalysts may be a robust alternative, and when coupled with photovoltaics, current-driven microbial carbon dioxide reduction represents a new form of photosynthesis that might convert solar energy to organic products more effectively than traditional biomass-based strategies.
Abstract: The possibility of providing the acetogenic microorganism Sporomusa ovata with electrons delivered directly to the cells with a graphite electrode for the reduction of carbon dioxide to organic compounds was investigated. Biofilms of S. ovata growing on graphite cathode surfaces consumed electrons with the reduction of carbon dioxide to acetate and small amounts of 2-oxobutyrate. Electrons appearing in these products accounted for over 85% of the electrons consumed. These results demonstrate that microbial production of multicarbon organic compounds from carbon dioxide and water with electricity as the energy source is feasible.
853 citations
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TL;DR: The results demonstrate that GAC can promote DIET and suggest that stimulation of metabolism in methanogenic digesters can be attributed, at least in part, to the high conductivity of GAC providing better interspecies electrical connections than those that can be forged biologically.
Abstract: Granular activated carbon (GAC) is added to methanogenic digesters to enhance conversion of wastes to methane, but the mechanism(s) for GAC's stimulatory effect are poorly understood. GAC has high electrical conductivity and thus it was hypothesized that one mechanism for GAC stimulation of methanogenesis might be to facilitate direct interspecies electron transfer (DIET) between bacteria and methanogens. Metabolism was substantially accelerated when GAC was added to co-cultures of Geobacter metallireducens and Geobacter sulfurreducens grown under conditions previously shown to require DIET. Cells were attached to GAC, but did not aggregate as they do when making biological electrical connections between cells. Studies with a series of gene deletion mutants eliminated the possibility that GAC promoted electron exchange via interspecies hydrogen or formate transfer and demonstrated that DIET in the presence of GAC did not require the electrically conductive pili and associated c-type cytochrome involved in biological interspecies electrical connections. GAC also greatly stimulated ethanol metabolism and methane production in co-cultures of G. metallireducens and Methanosarcina barkeri. Cells were attached to GAC, but not closely aggregated, suggesting little opportunity for biological electrical contacts between the species. GAC also enhanced methane production in samples from a methanogenic digester in which Methanosaeta were the predominant methanogens. The results demonstrate that GAC can promote DIET and suggest that stimulation of metabolism in methanogenic digesters can be attributed, at least in part, to the high conductivity of GAC providing better interspecies electrical connections than those that can be forged biologically.
702 citations
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University of Minho1, University of Porto2, Université Paris-Saclay3, Ghent University4, Institut national de la recherche agronomique5, University of Chieti-Pescara6, Slovak University of Agriculture7, University of Copenhagen8, University of Vigo9, Aarhus University10, Agricultural University of Athens11, University of Nantes12, Technical University of Denmark13
TL;DR: This review aims at helping scientists in finding the most appropriate and up-to-date methods to study their biofilms by giving a critical perspective, highlighting the advantages and limitations of several methods.
Abstract: Biofilms are widespread in nature and constitute an important strategy implemented by microorganisms to survive in sometimes harsh environmental conditions. They can be beneficial or have a negative impact particularly when formed in industrial settings or on medical devices. As such, research into the formation and elimination of biofilms is important for many disciplines. Several new methodologies have been recently developed for, or adapted to, biofilm studies that have contributed to deeper knowledge on biofilm physiology, structure and composition. In this review, traditional and cutting-edge methods to study biofilm biomass, viability, structure, composition and physiology are addressed. Moreover, as there is a lack of consensus among the diversity of techniques used to grow and study biofilms. This review intends to remedy this, by giving a critical perspective, highlighting the advantages and limitations of several methods. Accordingly, this review aims at helping scientists in finding the most appropriate and up-to-date methods to study their biofilms.
659 citations
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TL;DR: The known range of microorganisms capable of electrosynthesis is expanded, providing multiple options for the further optimization of this process.
Abstract: Microbial electrosynthesis, a process in which microorganisms use electrons derived from electrodes to reduce carbon dioxide to multicarbon, extracellular organic compounds, is a potential strategy for capturing electrical energy in carbon-carbon bonds of readily stored and easily distributed products, such as transportation fuels. To date, only one organism, the acetogen Sporomusa ovata, has been shown to be capable of electrosynthesis. The purpose of this study was to determine if a wider range of microorganisms is capable of this process. Several other acetogenic bacteria, including two other Sporomusa species, Clostridium ljungdahlii, Clostridium aceticum, and Moorella thermoacetica, consumed current with the production of organic acids. In general acetate was the primary product, but 2-oxobutyrate and formate also were formed, with 2-oxobutyrate being the predominant identified product of electrosynthesis by C. aceticum. S. sphaeroides, C. ljungdahlii, and M. thermoacetica had high (>80%) efficiencies of electrons consumed and recovered in identified products. The acetogen Acetobacterium woodii was unable to consume current. These results expand the known range of microorganisms capable of electrosynthesis, providing multiple options for the further optimization of this process.
593 citations
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TL;DR: The finding that biochar can stimulate DIET may be an important consideration when amending soils with biochar and can help explain why biochar may enhance methane production from organic wastes under anaerobic conditions.
Abstract: Biochar, a charcoal-like product of the incomplete combustion of organic materials, is an increasingly popular soil amendment designed to improve soil fertility. We investigated the possibility that biochar could promote direct interspecies electron transfer (DIET) in a manner similar to that previously reported for granular activated carbon (GAC). Although the biochars investigated were 1000 times less conductive than GAC, they stimulated DIET in co-cultures of Geobacter metallireducens with Geobacter sulfurreducens or Methanosarcina barkeri in which ethanol was the electron donor. Cells were attached to the biochar, yet not in close contact, suggesting that electrons were likely conducted through the biochar, rather than biological electrical connections. The finding that biochar can stimulate DIET may be an important consideration when amending soils with biochar and can help explain why biochar may enhance methane production from organic wastes under anaerobic conditions.
530 citations