Navegando por Autor "Araújo, Nathália Kelly de"

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Enhancing chitosan hydrolysis aiming chitooligosaccharides production by using immobilized chitosanolytic enzymes
(Elsevier, 2020-09) Santos, Everaldo Silvino dos; Dantas, Júlia Maria de Medeiros; Silva, Nayara Sousa da; Padilha, Carlos Eduardo de Araújo; Araújo, Nathália Kelly de
Chitooligosaccharides (COS) show interesting bioactivities, being a promising product for the pharmaceutical industry. The use of immobilized enzymes for the COS is interesting, as long as the enzyme is stable for industrial purposes. This paper investigated the best condition for immobilization of chitosanase, cellulase and β-glucosidase via adsorption and covalent bond aiming chitosan hydrolysis. For both strategies, the conditions were varied to define the best method for each enzyme, and then they were compared in stability tests. The results showed the optimum hydrolysis temperature for all enzymes was 55 °C, with pH 6.0 for chitosanase and cellulase and pH 4.0 for β-glucosidase. In relation to the immobilization by adsorption, the pH 5.0 was the best for all enzymes, and the enzyme load of 25 U/gsupport was the best for cellulase and chitosanase, while 50 U/gsupport was the best for β-glucosidase. Considering the immobilization by covalent bonding, the optimum conditions depend on the enzyme. For cellulase best result was using 25 U/gsupport and 0.5% (v/v) of glutaraldehyde. In relation to β-glucosidase it was 25 U/gsupport and 1.0% (v/v) of glutaraldehyde and for chitosanase was 50 U/gsupport and 0.5% (v/v) of glutaraldehyde. Immobilization steps improved the thermal stability of all enzymes. In addition, compared to β-glucosidase and cellulase, the chitosanase immobilized via adsorption showed a high operational stability, retaining 70% of the initial enzymatic activity after 6 cycles of hydrolysis. Thus, simple immobilization techniques prove to be a feasible methodology to be implemented in the chitooligosaccharides production
Exploiting films based on pectin extracted from yellow mombin (Spondias mombin L.) peel for active food packaging
(Springer Nature, 2021-01-30) Santos, Everaldo Silvino dos; Oliveira Júnior, Sérgio Dantas de; Araújo, Jaciara Silva de; Asevedo, Estefani Alves de; Medeiros, Fábio Gonçalves Macêdo de; Santos, Vinícius Silva dos; Sousa Júnior, Francisco Canindé de; Araújo, Nathália Kelly de
In this study, the potential of yellow mombin (Spondias mombin L.)–extracted pectin as a film-forming matrix for the elaboration of edible coatings was investigated. The films of chitosan, citric pectin, and carboxymethylcellulose (Sigma/USA) and natural pectin were prepared by casting. The film morphological characterization was performed by scanning electron microscopy (SME), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and atomic force microscopy (AFM). Additionally, total phenolic compounds (TPC), total antioxidant activity (TAC), DPPH scavenging capacity, and antimicrobial activity were assayed for the natural pectin–based films. The results showed that the film based on natural pectin presented a 46% degree of esterification that was higher than commercial (34%), showing its capacity of forming gels. The film formed by chitosan presented a very different behavior for loss of mass during TGA when compared to the other films, occurring a mass loss completely at 647.7 °C in 61 min. The value obtained from the concentration of total phenolics (mg GAE/100 g dried) found in the formulated film based on pectin was 3998.99 ± 42.64 and with solubility in water of almost 100%. Additionally, the scavenging of the DPPH radical with a value of 15.48 ± 1.48 μmol TE/g was found on the film based on natural pectin thus showing antioxidant capacity. Finally, this film showed less significant mechanical properties when compared to other films and a good pronounced antimicrobial effect against the gram-negative bacteria tested. Therefore, it could be potentially used for producing food-active packages
Histopathological prognosis of papillary thyroid carcinoma associated with nutritional status of vitamins A and E
(European Journal of Clinical Nutrition, 2021-07) Lyra, Clélia de Oliveira; Antoine, Lara Lima; Neri, Julianna Lys de Sousa Alves; Melo, Thaisa Cristina Tavares de; Leite, Isabela Samária Fernandes; Santos, Diego Marques da Costa; Araújo, Jéssica Nayara Góes de; Silva, Ana Gabriella da Costa Lemos; Araújo, Nathália Kelly de; Ramos, Carlos César de Oliveira; Tarrapp, Sheila Ramos de Miranda Henriques; Luchessi, André Ducati; Ribeira, Karla Danielly da Silva; Silbiger, Vivian Nogueira
Background/Objectives: Experimental and clinical studies have shown that vitamins A and E can inhibit cancer formation and progression. The unfavourable status of these vitamins can represent risk factors for the disease. This study aimed to evaluate the associations between the nutritional status of vitamins A and E (serum levels and dietary intake) and histopathological outcomes in Papillary Thyroid Carcinoma (PTC) patients. Subjects/Methods: We applied a cross-sectional study (2017–2018) and quantified retinol (ROH) and α-tocopherol (TOH) serum levels and vitamins dietary intake of 46 PTC patients. Serum vitamins were quantified by high efficiency liquid chromatography and vitamins dietary intake was analyzed by 24‐hr dietary recalls. Results: Patients with lower ROH serum levels were more likely to present lymph node metastasis and/or angiolymphatic invasion (p = 0.025). In addition, higher vitamin A and vitamin E intake are related to the absence of extrathyroidal extension (p = 0.013) and lymph node metastasis (p = 0.007), respectively. Our findings suggest that a ROH serum level greater than 2.65 μmol/L in PTC patients may be a protective factor against the presence of lymph node metastasis and angiolymphatic invasion. In addition, vitamin A and E intake may protect against extrathyroidal extension and lymph node metastasis. Conclusions: A favourable nutritional status (higher serum levels and/or intake) of vitamin A and E may be associated with less aggressive tumours in PTC patients
Ion exchange expanded bed chromatography for the purification of an extracelular chitosanase from Bacillus cereus
(BMC Proceedings, 2014-10-01) Santos, Everaldo Silvino dos; Xavier, Maria Luiza Oliveira; Araújo, Nathália Kelly de; Macedo, Gorete Ribeiro de
Oligosaccharides have gained considerable interest in the pharmaceutical chemical, food and medical area, due to their biological properties such as the antibacterial [1], antifungal [2], prebiotic, antidiabetic, immunostimulating and antimutagenic activity, acceleration of calcium absorption, recovery of tissue stimulation and activation of plant resistance against insects and pathogen attacks [3], and antitumor functions [4], and thus have been used in agriculture, food and pharmaceutical industries [5]. The enzyme chitosanase is commonly used in the hydrolysis of chitosan. In this work, the ion exchange Streamline DEAE resin was used on an expanded bed system for chitosanase studies purification. In the first step the adsorption characteristic was determined, followed by the comparison between expansion degree using crude unclarified broth and cell-free
Modeling and simulation of Bacillus cereus chitosanase activity during purification using expanded bed chromatography
(Springer, 2016-07) Souza, Domingos Fabiano de Santana; Padilha, Carlos Eduardo de Araújo; Araújo, Nathália Kelly de; Oliveira, Jackson Araújo de; Macedo, Gorete Ribeiro de; Santos, Everaldo Silvino dos
−A phenomenological model was used to describe sequentially the three steps (flowthrough, washing and elution) of expanded bed adsorption chromatography for recovery of chitosanases from Bacillus cereus. Additionally, a hybrid strategy for model parameter estimation was carried out using particle swarm optimization and Gauss-Newton algorithms. The model was validated with independent experimental data and the statistical criteria (χ2 and mean squared error tests) showed that the hybrid strategy was more promising than just the heuristic method. With the calibrated model, surface response methodology was applied to obtain the optimal operational conditions, and experiments were performed to confirm these results. Overall, a value of 41.08% for yield was obtained using 700 mM NaCl during elution. In summary, all approach employed in this work was relevant for maximizing the yield of the chromatographic process
Physicochemical characterization, fatty acid profile, antioxidant activity and antibacterial potential of cacay oil, coconut oil and cacay butter
(Plos One, 2020-04) Damasceno, Karla Suzanne Florentino da Silva Chaves; Azevedo, Wendell Medeiros de; Oliveira, Larissa Ferreira Ribeiro de; Alcântara, Maristela Alves; Cordeiro, Angela Maria Tribuzy de Magalhães; Araújo, Nathália Kelly de; Assis, Cristiane Fernandes de; Sousa Júnior, Francisco Caninde de
The Amazon region is rich in genetic resources such as oilseeds which have potentially important local commercial exploitation. Despite its high concentration of bioactive compounds, cacay (Caryodendron orinocense Karst.) oil is poorly investigated and explored. Thus, this study focuses on the physicochemical characterization (moisture, density, and saponification, iodine, and acidity values), fatty acid composition as determined by gas chromatograph mass spectrometry (GC/MS), total phenolic content (TPC), and antioxidant activity (DPPH and ABTS radical scavenging assay) of cacay oil, coconut oil and a coconut/cacay oil blend, also known as cacay butter. The antibacterial activity of cacay oil was additionally evaluated. Our study demonstrated that cacay oil presents a high amount of polyunsaturated fatty acid (PUFA) (58.3%) with an emphasis on linoleic acid and a lower acidity value (2.67 ± 0.01 cg I2/g) than butter and coconut oil, indicating a low concentration of free fatty acids. In contrast, cacay butter and coconut oil presented higher saturated fatty acid percentages (69.1% and 78.4%, respectively) and higher saponification values (242.78 and 252.22 mg KOH/g, respectively). The samples showed low moisture and relative density between 912 and 916 kg/m3 . The hydrophilic fraction of cacay oil was highlighted in the quantification of TPC (326.27 ± 6.79 mg GAE/kg) and antioxidant capacity in vitro by DPPH radical scavenging assay (156.57 ± 2.25 μmol TE/g). Cacay oil inhibited the growth of Bacillus cereus (44.99 ± 7.68%), Enterococcus faecalis (27.76 ± 0.00%), and Staphylococcus aureus (11.81 ± 3.75%). At long last, this is the first study reporting the physicochemical characterization and bioactive properties of cacay butter. Coconut oil and cacay butter showed great oxidative stability potential due to higher contents of saturated fatty acids. Moreover, cacay oil presents as an alternative source of raw materials for cosmetic and biotechnology industries due to its high concentration of PUFA and for being a rich source of phenolic compounds
Production of enzymes by paenibacillus chitinolyticus and paenibacillus ehimensis to obtain chitooligosaccharides
(Springer, 2013-03-17) Santos, Everaldo Silvino dos; Araújo, Nathália Kelly de; Assis, Cristiane Fernandes de; Macedo, Gorete Ribeiro de; Farias, Louise Fonseca de; Arimatéia Júnior, Humberto; Pedrosa, Matheus de Freitas Fernandes; Pagnoncelli, Maria Giovana Binder
Obtaining oligosaccharides from chitosan has been the focus of several studies in the pharmaceutical, chemical, food, and medical areas, due to their functional properties. Here, we evaluated the production potential of biologically functional chitooligosaccharides using enzymes extracts produced by Paenibacillus chitinolyticus and Paenibacillus ehimensis. After 48 h of fermentation, these microorganisms were able to produce chitosanases, which generated oligomers with a degree of polymerization between dimers and hexamers. The maximum conversion of chitosan to oligomers was 99.2 %, achieved after 12 h incubation of chitosan with enzymes produced by P. ehimensis. The chitooligosaccharides generated were capable of scavenging the 2,2-diphenyl-1-picrylhydrazyl radical, reaching a maximum scavenging rate of 61 and 39 % when produced with P. ehimensis and P. chitinolyticus enzymes, respectively. The use of these enzymes in the crude form could facilitate their use in industrial applications
Purificação de quitosanases produzidas por Bacillus cereus utilizando cromatografía líquida rápida de proteínas
(Universidade Federal do Rio Grande do Norte, 2017-06) Dantas, Julia Maria de Medeiros; Santos, Everaldo Silvino dos; Araújo, Nathália Kelly de; Sousa Júnior, Francisco Canindé de; Padilha, Carlos Eduardo de Araújo
O Rio Grande do Norte é historicamente um grande produtor e consumidor de camarão, sendo, portanto, um grande gerador dos resíduos provenientes do beneficiamento deste produto. O rejeito do camarão, seu exoesqueleto, é rico em quitina. Esta é matéria prima para obtenção da quitosana, a qual é gerada com a desacetilação da quitina. A quitosana é rica em propriedades biológicas, porém existe dificuldade de manipulação devido a sua baixa solubilidade em água. A hidrólise da quitosana gera quitooligossacarídeos (QOS), que possuem diversas propriedades biológicas, como antimicrobiana, antitumoral, antiinflamatória e anti-citotóxica, apresenta maior solubilidade em água. A obtenção dos QOS por hidrólise enzimática possui diversas vantagens industriais quando comparada, por exemplo, com a hidrólise ácida. Porém, para a utilização de enzimas em produtos para fins medicinais e farmacêuticos, é necessário que elas possuam um alto fator de purificação. Por isso é importante o desenvolvimento de metodologias de purificação de baixo custo e eficientes para tal produto. Dessa forma, este trabalho foi realizado para avaliar o desempenho do sistema de cromatografia AKTA Plus para a purificação de quitosanases produzidas a partir do Bacillus cereus. Nosso grupo de pesquisa já realizou trabalho de purificação dessa enzima, porém em cromatografia de bancada. Foi utilizada uma coluna de leito fixo, com resina de troca iônica aniônica (Streamline DEAE), e aplicado um gradiente linear de 0 a 1 M de NaCl na etapa eluição das proteínas da matriz adsorvente. De modo geral o sistema AKTA Plus apresentou uma boa performance na purificação da enzima, obtendo o melhor resultado na eluição com uma concentração de 0,25 M de NaCl, com um fator de purificação de 9,54. Na avaliação geral do processo de eluição, a primeira fração integrada (0,05-0,25 M de NaCl) da eluição obteve como resultado um fator de purificação de 2,7. O ponto individual de melhor fator de purificação obteve um rendimento de 7,27% (0,20 M de NaCl) e a fração integrada da eluição com o melhor rendimento (18,96%) foi na faixa de 0,30-0,55 M de NaCl. A purificação dessa enzima utilizando este sistema trouxe um considerável incremento do fator de purificação comparando com a metodologia inicialmente empregada pelo nosso grupo.
Recovery and puriﬁcation of chitosanaseproduced by Bacillus cereus using expandedbed adsorption and central composite design
(Wiley, 2016-02) Santos, Everaldo Silvino dos; Macedo, Gorete Ribeiro de; Araújo, Nathália Kelly de; Pimentel, Vanessa Carvalho; Silva, Nayane Macedo Portela da; Padilha, Carlos Eduardo de Araújo
This study presents a system for expanded bed adsorption for the puriﬁcation of chitosanasefrom broth extract in a single step. A chitosanase-producing strain was isolated and identiﬁedas Bacillus cereus C-01 and used to produce chitosanases. The expanded bed adsorptionconditions for chitosanase puriﬁcation were optimized statistically using STREAMLINETMDEAE and a homemade column (2.6 × 30.0 cm). Dependent variables were deﬁned by thequality criteria puriﬁcation factor (P) and enzyme yield to optimize the chromatographicprocess. Statistical analyses showed that the optimum conditions for the maximum P were150 cm/h load ﬂow velocity, 6.0 cm settled bed height, and 7.36 cm distributor height.Distributor height had a strong inﬂuence on the process, considerably affecting both theP and enzyme yield. Optimizing the puriﬁcation variables resulted in an approximately3.66-fold increase in the P compared with the value under nonoptimized conditions. Thissystem is promising for the recovery of chitosanase from B. cereus C-01 and is economicallyviable because it promotes the reduction steps
Single-step purification of chitosanases from Bacillus cereus using expanded bed chromatography
(Elsevier, 2016-01) Santos, Everaldo Silvino dos; Araújo, Nathália Kelly de; Pagnoncelli, Maria Giovana Binder; Pimentel, Vanessa Carvalho; Xavier, Maria Luiza Oliveira; Padilha, Carlos Eduardo Araújo; Macedo, Gorete Ribeiro de
A chitosanase-producing strain was isolated and identified as Bacillus cereus C-01. The purification and characterization of two chitosanases were studied. The purification assay was accomplished by ion exchange expanded-bed chromatography. Experiments were carried out in the presence and in the absence of cells through different expansion degree to evaluate the process performance. The adsorption experiments demonstrated that the biomass does not affect substantially the adsorption capacity of the matrix. The enzyme bound to the resin with the same extent using clarified and unclarified broth (0.32 and 0.30 U/g adsorbent, respectively). The fraction recovered exhibited 31% of the yield with a 1.26-fold increase on the specific activity concerned to the initial broth. Two chitosanases from different elution steps were recovery. Chit A and Chit B were stable at 30–60 ◦C, pH 5.5–8.0 and 5.5–7.5, respectively. The highest activity was found at 55 ◦C, pH 5.5 to Chit A and 50 ◦C, pH 6.5 to Chit B. The ions Cu2+, Fe2+ and Zn2+ indicated inhibitory effect on chitosanases activities that were significantly activated by Mn2+. The methodology applied in this study enables the partial purification of a stable chitosanase using a feedstock without any pre-treatment using a single-step purification

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Navegando por Autor "Araújo, Nathália Kelly de"