Percorrer por autor "Fernandes, Pedro Carlos de Barros"

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    A biotecnologia na conservação do património cultural
    (Edições Universitárias Lusófonas, 2007) Fernandes, Pedro Carlos de Barros; Escola de Comunicação, Arquitetura, Artes e Tecnologias da Informação
    O papel da biotecnologia na sociedade contemporânea está habitualmente associado às áreas da medicina e da agricultura e ao desenvolvimento de processos de produção à escala industrial, menos poluentes e tão ou mais eficientes que os processos químicos existentes. Verificou-se recentemente que o potencial e as ferramentas da biotecnologia podem ser aplicados com grande eficiência nas complexas tarefas associadas à conservação e restauro de obras de arte. O presente trabalho visa ilustrar os campos específicos nos quais já se estabeleceu uma eficiente interacção entre arte e biotecnologia. Com efeito, a contribuição desta última para a conservação do património cultural já se efectiva ao nível de: Identificação de agentes biológicos causa dores de degradação; Desenvolvimento de estratégias e ferramentas adequadas ao combate e erradicação dos agentes degradativos sem prejuízo da qualidade da obra tratada; Identificação por métodos de biologia molecular dos materiais de origem biológica utilizados em obras de arte. A par das abordagens já implementadas, pretende-se ainda apresentar perspectivas de desenvolvimentos futuros desta estratégia, nomeadamente ao nível do desenvolvimento de biosensores para a monitorização e controlo do estado de preservação e restauro de obras de arte.
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    Improvement of Aglycone Content in Soy Isoflavones Extract by Free and Immobilized β-Glucosidase and Their Effects in Lipid Accumulation
    (Edições Universitárias Lusófonas, 2020-06) Angelotti, Joelise; Dias, Fernanda; Sato, Hélia; Fernandes, Pedro Carlos de Barros; Nakajima, Vânia; Macedo, Juliana; Faculdade de Engenharia
    Soybean is one of the most important commodities in the world, being applied in feed crops and food, pharmaceutical industries in different ways. Soy is rich in isoflavones that in aglycone forms have exhibited significant anti-obesity and anti-lipogenic effects. Obesity is a global problem as several diseases have been related to this worldwide epidemic. The aim of this work was to verify the effect of free and immobilized β-glucosidase, testing Lentikats, and sol–gel as carriers. Moreover, we wanted to examine if the different types of hydrolysis would generate extracts with distinct biological activity concerning lipid accumulation, PPAR-α regulation, and TNF-α, IL-6, and IL-10 concentrations using in vitro assays. Our results show that all formulations of β-glucosidase could hydrolyze soy isoflavones. Thus, after 24 h of incubation, daidzein content increased 2.6-, 10.8-, and 12.2-fold; and genistein content increased 11.7, 11.4, and 11.4 times with the use of free enzyme, Lentikats®, and sol–gel immobilized enzyme, respectively. Moreover, both methodologies for enzyme immobilization led to promising forms of biocatalysts for application in the production of soy extracts rich in isoflavones aglycones, which are expected to bring about health benefits. A mild lipogenic effect was observed for some concentrations of extracts, as well as a slight inhibition in PPAR-α expression, although no significant differences were noticeable in the cytokines TNF-α, IL-10, and IL-6 as compared with the control.
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    Inulinase from Rhodotorula mucilaginosa: immobilization and application in the production of fructooligosaccharides
    (Edições Universitárias Lusófonas, 2021) Ribeiro, Geise Camila de Araújo; Fernandes, Pedro Carlos de Barros; Silva, Dayse Alessandra Almeida; Brandão, Hugo Neves; Assis, Sandra Aparecida de; Faculdade de Engenharia
    The crude extract containing inulinase from Rhodotorula mucilaginosa was obtained by submerged fermentation. Inulinase was immobilized on chicken eggshell by physical adsorption and covalent crosslinking, using glutaraldehyde as a crosslinking reagent, and Celite by adsorption. Fructooligosaccharides production was performed using immobilized inulinase (5%, w/v) and inulin substrate solution under experimental conditions evaluated through Doehlert experimental design. The production of inulinase was optimized for concentrations of D-glucose and yeast extract at 12.5 and 0.5 g/L, respectively, resulting in an optimal activity of 0.62 U. The optimal pH and temperature for enzyme activity were 8.0 and 75 °C, respectively, leading to an optimal activity of 3.54 U. The highest immobilization efficiency (46.27%) was obtained upon immobilization on Celite. Immobilization by adsorption to eggshell allowed for specific activity of 4.15 U/g, and adsorption to Celite resulted in specific activity of 3.70 U/g. The highest titer in fructooligosaccharides was obtained with an initial inulin concentration of 250 g/L (25%, w/v), and a reaction time of 16 h. Hence, immobilized inulinase proved to be a promising catalyst for fructooligosaccharides production since the formulation is performed through a simple, low-cost, and large-scale applicable methodology.
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    Multi-enzyme systems in flow chemistry
    (Edições Universitárias Lusófonas, 2021) Fernandes, Pedro Carlos de Barros; Carvalho, Carla C. C. R. de; Faculdade de Engenharia
    Recent years have witnessed a growing interest in the use of biocatalysts in flow reactors. This merging combines the high selectivity and mild operation conditions typical of biocatalysis with enhanced mass transfer and resource efficiency associated to flow chemistry. Additionally, it provides a sound environment to emulate Nature by mimicking metabolic pathways in living cells and to produce goods through the systematic organization of enzymes towards efficient cascade reactions. Moreover, by enabling the combination of enzymes from different hosts, this approach paves the way for novel pathways. The present review aims to present recent developments within the scope of flow chemistry involving multi-enzymatic cascade reactions. The types of reactors used are briefly addressed. Immobilization methodologies and strategies for the application of the immobilized biocatalysts are presented and discussed. Key aspects related to the use of whole cells in flow chemistry are presented. The combination of chemocatalysis and biocatalysis is also addressed and relevant aspects are highlighted. Challenges faced in the transition from microscale to industrial scale are presented and discussed
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    Mycobacterium vaccae adaptation to disinfectants and hand sanitisers, and evaluation of cross-tolerance with antimicrobials
    (Edições Universitárias Lusófonas, 2020) Carvalho, Carla C. C. R. de; Teixeira, Raquel; Fernandes, Pedro Carlos de Barros; Faculdade de Engenharia
    Mycobacterium vaccae is being considered as an adjuvant to antituberculosis therapy, tested for the treatment of autoimmune diseases, and as an anti-depressive agent. This bacterium is ubiquitous in the environment and the widespread use of disinfectants and sanitisers may lead to its adaptation to these compounds. In the present study, M. vaccae cells adapted to these compounds mainly by making adjustments in their lipid composition and net surface charge. The modifications in the lipid composition led to changes in membrane permeability which resulted in increased tolerance towards levofloxacin, thioridazine, and omeprazole.
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    Production, characterization, and immobilization of protease from the yeast Rhodotorula oryzicola
    (Edições Universitárias Lusófonas, 2020) Oliveira, Juliana Mota de; Fernandes, Pedro Carlos de Barros; Benevides, Raquel Guimarães; Assis, Sandra Aparecida de; Faculdade de Engenharia
    The protease was produced extracellularly in submerged fermentation by the yeast Rhodotorula oryzicola using different sources of nitrogen and maximum activity (6.54 × 10−3 U/mg) was obtained in medium containing 2% casein (w/v). Purification of the protease by gel filtration chromatography resulted in a 3.07-fold increase of specific protease activity. The optimal pH and temperature for enzyme activity were 6.51 and 63.04 °C, respectively. Incubation in the presence of some salts enhanced enzyme activity, which peaked under 0.01 M BaCl2. The enzyme retained about 90% of enzymatic activity at temperatures 50–60 °C. The commercially available enzyme carriers evaluated, silica gel, Celite 545, and chitosan effectively immobilized the protease. The enzyme immobilized in Celite 545 retained 73.53% of the initial activity after 15 reuse cycles. These results are quite promising for large-scale production and immobilization of protease from R. oryzicola, as the high operational stability of the immobilized enzyme lowers production costs in biotechnological applications that require high enzymatic activity and stability under high temperatures.
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    Upgrading end-of-line residues of the red seaweed Gelidium sesquipedale to polyhydroxyalkanoates using Halomonas boliviensis
    (Edições Universitárias Lusófonas, 2020-09) Tuna, Stepan; Izaguirre, Jon; Bondar, Marina; Marques, Mafalda; Fernandes, Pedro Carlos de Barros; Fonseca, Maria Manuela Regalo da; Cesário, Maria; Faculdade de Engenharia
    Agar extraction from Gelidium and Gracilaria red seaweed species produces hundred thousand ton of carbohydrate-rich residues annually. Gelidium sesquipedale waste biomass obtained after agar extraction, still contained 44.2 % w/w total carbohydrates (dry-weight basis). These residues were biologically up-graded to poly-3-hydroxybutyrate (P3HB) after saccharification of their carbohydrate fraction to simple sugars. A combined hydrolysis treatment using sulfamic acid followed by enzymatic hydrolysis with cellulases produced a glucose-rich hydrolysate with a negligible content of inhibitors. With this treatment a sugar yield of circa 30 % (g glucose/g biomass) was attained. The algal hydrolysates were assessed as carbon source for the production of P3HB by the halotolerant bacteria Halomonas boliviensis. A cell concentration of 8.3 g L−1 containing 41 % (w/w) of polymer and a yield (YP/S) of 0.16 gpolymer/gglucose were attained in shake flask assays. In this work, cellulose-rich seaweed waste was shown to be an upgradable, sustainable source of carbohydrates.