ITQB: BEM - PhD Theses
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- Understanding energy and hydrogen metabolism in sulfate-reducing bacteriaPublication . Pereira Manteigas, Gonçalo Gabriel; Pereira, Inês Cardoso; Duarte, Américo"Molecular hydrogen (H2) is a promising alternative energy carrier due to its high energy content and absence of greenhouse gas emissions, but its natural abundance is low and it must be generated, usually through energy-intensive processes. Sulfate-reducing prokaryotes (SRP) are interesting microorganisms for H2 production, as they typically have many hydrogenases, the enzymes responsible for producing and/or oxidizing H2. SRP are found in anoxic environments, where they play a pivotal role in both the carbon and sulfur cycles. These microorganisms use highly conserved respiratory membrane complexes to couple the oxidation of H2 or carbon compounds with the dissimilatory reduction of sulfate or sulfite.(...)"
- Novel Insights into the Catalytic Mechanism of the W-FdhAB from Desulfovibrio vulgaris HildenboroughPublication . Rebelo Manuel, Rita"It is known that the world is facing the negative environmental impacts of fossil fuel utilization. In 2023, a total of 37.4 Gt of CO2 was released to the atmosphere, having erects in atmospheric warming, precipitation patterns, and sea level rise. The use of CO2 as a feedstock to generate added-value products is an alternative to decrease atmospheric CO2 levels in order to create a CO2 circular economy. Formate is an example of one of those products, being considered an alternative liquid fuel, which is safer to store and transport than H2. The W-containing formate dehydrogenase AB (FdhAB) from Desulfovibrio vulgaris Hildenborough catalyzes the interconversion of CO2 and formate. This enzyme has interesting characteristics amongst Fdhs – it has a high CO2 reduction activity, a simple structure, it can be handled in aerobic conditions and has an established expression system.(...)"
- Unraveling the metabolic pathway of dissimilatory sulfate reductionPublication . Ferreira, Delfim; Cardoso Pereira, Inês"Sulfate-reducers are anaerobic organisms from the Bacteria and Archaea domains of life, which are able to use a wide variety of electron donors and couple them with the reduction of sulfur molecules to hydrogen sulfide. This process, known as dissimilatory sulfate reduction, drives the biogeochemical sulfur cycle and has a strong influence on other element cycles and on the redox balance of the oceans and atmosphere.(...)"
- Unravelling the role of DsrD and DsrMKJOP in dissimilatory sulfite reductionPublication . Barbosa, Ana C. C.; Cardoso Pereira, InêsDissimilatory sulfate reduction is considered one of the most ancient microbial metabolic pathways on Earth. Anaerobic bacteria and archaea derive energy through this metabolic pathway, and they are widespread in anoxic habitats, such as marine sediments, freshwater sediments, soils, and the human gut. Sulfate-reducing microorganisms play a major role in the global cycling of carbon and sulfur, and they use sulfate as a terminal electron acceptor in the degradation of organic matter or hydrogen to produce hydrogen sulfide, a highly toxic gas. These microorganisms can have both a positive and negative impact, having implications for human health, climate change, biogeochemistry, and bioremediation.
- Biocatalytic reduction of carbon dioxide for sustainable biofuel productionPublication . Oliveira, Ana Rita; Pereira, Inês Cardoso"The development of sustainable processes to reduce CO2 levels is an urgent and challenging issue faced by our society. The use of CO2 as a feedstock for the production of added-value products, such as formate, represent a promising tool to mitigate CO2 emissions. This approach provides not only a mechanism to reduce harmful CO2 levels, (...)"
- Biologic Interconversion of Hydrogen and FormatePublication . Mourato, Cláudia Alhinho; Pereira, Inês Cardoso"Hydrogen (H2) is one of the most promising energy vehicles in alternative to the use of fossil fuels. However, in order to use H2 as energy carrier it is necessary to find a safe, economically viable, and reasonably sized solution to store and transport it. Formate has emerged as an ideal storage compound for H2 as it is a safe compound, liquid at room temperature, which can be easily stored and transported, and furthermore it allows the sequestration of CO2 in a valuable commodity chemical. Nevertheless, for the implementation of a H2 and formate economy it is crucial to find efficient processes that can be used either for the use of formate as storage material for H2 production or for the conversion of H2 and CO2 to formate.(...)"
- Novel insights into dissimilatory sulfite reductionPublication . Santos, André Fernando; Pereira, Inês CardosoLife on Earth is extremely diverse, as organisms had to adapt to a panoply of different environmental niches. There are several mechanisms by which organisms grow in the absence of oxygen, one of which is the dissimilatory reduction of sulfate to sulfide, performed by sulfate reducing prokaryotes (SRP). This is thought to be one of the most ancient biological metabolisms to have developed on earth. In SRP sulfate is first imported to the cytoplasm where it is activated by Sulfate adenylyl transferase to adenosine 5′-phosphosulfate (APS) in an ATP consuming process. After, the adenylyl-sulfate reductase is the enzyme responsible for the reduction of APS to sulfite.(...)
- Structural and functional studies of a high activity NiFeSe HydrogenasePublication . Marques, Marta Franco Coimbra; Pereira, Inês Cardoso; Matias, PedroTheawareness that fossil fuels exist in limited quantities has stimulated research into energy production from renewable sources. Future energy sources! should! be! plentiful! with! negligible! impact! on! the! environment.! Hydrogen!has!the!potential!to!satisfy!these!requirements.!Nevertheless,!current! methods! of! H2! production! rely! on! nonOrenewable! resources.! Biological! H2! production! from! sunlight! or! biomass! is! an! appealing! alternative! to! current! production!methods.!!(...)
- Study of novel energy metabolism pathways in anaerobic bacteriaPublication . Ramos, Ana Raquel Martinho; Pereira, Inês CardosoEnergy conservation in chemotrophic anaerobic bacteria is achieved by two possible processes, substrate level phosphorylation (SLP) and electron transfer phosphorylation (ETP). This second mechanism, also known as respiration, involves chemiosmotic coupling. However, a third mechanism for energy coupling was recently proposed: the flavin-based electron bifurcation (FBEB). (...)
- Electron transfer chains in sulfate reducing bacteriaPublication . Venceslau, Sofia Cristina dos Santos; Pereira, Inês A. Cardoso; Saraiva, Lígia M.The dissimilatory reduction of sulfur compounds (i.e.sulfate/sulfite reduction and sulfur disproportionation) is considered to have been one of the earliest metabolic processes on Earth able to sustain life. Dissimilatory sulfate reduction, using sulfate as an electron acceptor and organic compounds or hydrogen as electron donors, plays a significant role in the global sulfur and carbon cycles.(...)