Chromatographic study of sitagliptin and ertugliflozin under quality-by-design paradigm

Abstract The present study entails the systematic development and validation of a stability-indicating RP-HPLC method for the analysis of sitagliptin and ertugliflozin in a fixed-dose combination. Analytical quality by design (AQbD) concepts were used to define critical method variables, employing Pareto risk assessment and a Placket-Burman screening design, preceded by a Box-Behnken design with response surface analysis to optimise critical method parameters such as % acetonitrile (X1), buffer pH (X2) and column oven temperature (X3). Multiple response optimisation (Derringer's desirability) of variables was accomplished by studying critical analytical attributes, such as resolution, retention time and theoretical plates. The title analytes were separated effectively on a PRONTOSIL C18 column at 37 °C using a mobile phase of acetonitrile:acetate buffer, pH 4.4 (36:64 percent v/v), pumped at a flow rate of 1 mL/min, and UV detection at 225 nm. Linearity was observed over a concentration range of 25-150 µg/mL and 3.75-22.5 µg/mL at retention times of 2.82 and 3.92 min for sitagliptin and ertugliflozin, respectively. The method obeyed all validation parameters of the ICH Q2(R1) guidelines. The proposed robust method allows the study of the selected drugs in pharmaceutical dosage forms as well as in drug stability studies under various stress conditions.

Modulating the production of xylanase by Bacillus pumilus BS131 through optimization using waste fiber sludge / Modulando a produção de xilanase por Bacillus pumilus BS131 por meio da otimização usando lodo de fibra residual

Abstract In recent days, cheapest alternative carbon source for fermentation purpose is desirable to minimize production cost. Xylanases have become attractive enzymes as their potential in bio-bleaching of pulp and paper industry. The objective of the present study was to identify the potential ability on the xylanase production by locally isolated Bacillus pumilus BS131 by using waste fiber sludge and wheat bran media under submerged fermentation. Culture growth conditions were optimized to obtain significant amount of xylanase. Maximum xylanase production was recorded after 72 hours of incubation at 30 °C and 7 pH with 4.0% substrate concentration. In the nutshell, the production of xylanase using inexpensive waste fiber sludge and wheat-bran as an alternative in place of expensive xylan substrate was more cost effective and environment friendly.

Resumo Nos últimos dias, a fonte alternativa de carbono mais barata para fins de fermentação é desejável para minimizar o custo de produção. As xilanases têm se tornado enzimas atraentes como seu potencial no biobranqueamento da indústria de papel e celulose. O objetivo do presente estudo foi identificar a capacidade potencial na produção de xilanase por Bacillus pumilus BS131 isolado localmente usando lodo de fibra residual e farelo de trigo em meio de fermentação submersa. As condições de crescimento da cultura foram otimizadas para obter uma quantidade significativa de xilanase. A produção máxima de xilanase foi registrada após 72 horas de incubação a 30 °C e pH 7 com concentração de substrato de 4,0%. Resumindo, a produção de xilanase usando lodo de fibra residual de baixo custo e farelo de trigo como uma alternativa no lugar do substrato de xilano caro foi mais econômica e ecológica.

Erosive potential associated with the pH of industrialized and natural drinks

Nowadays there is an increase in the consumption of acidic drinks, especially the fermented ones. Its ingestion is closely associated with the demineralization of superficial dental tissues, which characterizes dental erosion. The objective of this study was to evaluate the pH of industrialized and natural drinks. The sample consisted of soft drinks, natural and artificial juices, fermented drinks, isotonic drinks and energy from different commercial brands acquired in the city of Niterói (RJ). The products were kept at room temperature (25oC) for 1 hour and were aliquoted 3 mL of each drink to a Becker to measure pH in a specific electrode coupled to a potentiometer. The readings were performed in triplicate. The mean pH ranged from 2.34 to 4.31, the most acidic drink was the refrigerant and the less acidic, the curd. It was found that all drinks analyzed had an acidic pH. Thus, potentially erosive dental structures.

Atualmente, há um aumento no consumo de bebidas ácidas, especialmente as fermentadas. Sua ingestão está intimamente associada à desmineralização dos tecidos dentários superficiais, o que caracteriza a erosão dentária. O objetivo da presente pesquisa foi avaliar o potencial erosivo de bebidas industrializadas e naturais. A amostra de conveniência foi constituída de refrigerantes, sucos naturais e artificiais, bebidas fermentadas, isotônicos e energéticos de diferentes marcas comerciais adquiridas no município de Niterói (RJ). Os produtos foram mantidos em temperatura ambiente (25oC) durante 1 hora e foram aliquotados 3 mL de cada bebida para um Becker para a mensuração de pH em eletrodo específico acoplado a um potenciômetro. As leituras foram realizadas em triplicata. Os valores médios de pH variaram de 2,34 a 4,31, sendo a bebida mais ácida um refrigerante e a menos ácida, a coalhada. Constatou-se que todas as bebidas analisadas apresentaram um pH ácido e abaixo do crítico para a dissolução do esmalte, sendo estas potencialmente erosivas das estruturas dentárias.

Anti-inflammatory effects and acute oral toxicity of Copaifera spp. essential oil-loaded nanoemulsion / Efectos antiinflamatorios y toxicidad oral aguda de nanoemulsión cargada de aceite esencial de Copaifera spp

Copaifera spp. essential oil (EOC) was extracted by hydrodistillation of Copaifera oleoresin (COR). The EOC was characterized by GC/MS and a novel EOC-loaded nanoemulsion was developed to enhance the EOC solubility and to evaluate its utility as antinflammatory. EOC contain 14 volatile compounds (including ß-caryophyllene: 51.52%) having a required HLB of 11. The Surfactant: EOC: Water ratio of 13:15:75 (%, w:w:w) produced the optimal formulation (particle size: 94.47 nm). The EOC-loaded nanoemulsion presented a pseudoplastic/thixotropic behavior with excellent shelf stability for 6 months. The anti-inflammatory effect of the nanoemulsion was more potent than that of the EOC, and statistically equal to diclofenac (50 mg/kg). The EOC-loaded nanoemulsion showed no oral acute toxicity (in mice) at 2000 mg/kg; hence, it is considered a nontoxic product. The development of the EOC-loaded nanoemulsion added value to both the COR and the EOC by providinga suitable formulation that could be used as an anti-inflammatory product.

El aceite esencial (EOC) fue extraído por hidrodestilación de oleoresina de Copaifera spp. El EOC fue caracterizado químicamente por GC/MS. Se formuló una nanoemulsión con EOC para mejorar la solubilidad del EOC y evaluar su utilidad como antiinflamatorio. El EOC contiene 14 compuestos volátiles (incluido el ß-cariofileno: 51,52%) con un HLB requerido de 11. La relación Tensioactivo: EOC: Agua de 13:15:75 (%, p:p:p) produjo la formulación óptima (tamaño de partícula: 94,47 nm).. La nanoemulsión cargada con EOC presentó un comportamiento pseudoplástico/tixotrópico con una excelente estabilidad en almacenamiento durante 6 meses. El efecto antiinflamatorio de la nanoemulsión fue más potente que el del EOC y estadísticamente igual al diclofenaco (50 mg/kg). La nanoemulsión cargada con COE no mostró toxicidad aguda oral (en ratones) a 2000 mg/kg; por lo tanto, se considera un producto no tóxico. El desarrollo de la nanoemulsión cargada con EOC agregó valor tanto al COR como al EOC al proporcionar una formulación adecuada que podría usarse como un producto antiinflamatorio.

Fórmula artesanal a base de lactosuero: complemento alimenticio para niños preescolares / Artisanal whey-based formula: food supplement for preschool children

Resumen Se pretendió desarrollar una fórmula artesanal, a base de lactosuero, como complemento alimenticio para niños preescolares. Se realizó una investigación descriptiva ejecutada en tres fases: 1. Ensayos preliminares para la determinación del esquema tecnológico; 2. Evaluación fisicoquímica para la caracterización del producto y determinación de macronutrientes y 3. Evaluación sensorial donde se midió el nivel de agrado del producto final. Los datos obtenidos de los análisis se tabularon en cuatro repeticiones y se analizaron a través de estadísticas descriptivas de tendencia central y en frecuencias expresadas en tablas y gráficos mediante el programa estadístico SPSS versión 20.0. Se obtuvo que en el análisis proximal del requesón deshidratado, éste aportó por cada 100 gramos de producto: 480,28 kcal, 46,5% de proteínas, 22,36% de grasas y 23,26% de hidratos de carbono. La formulación final de la bebida constó de 2,9 g de requesón deshidratado, 3,6 g de arroz previamente cocido y 1,8 g de azúcar diluidos por cada onza preparada. Se determinó que es una fórmula hipocalórica-hiperproteica e isoosmolar, con una viscosidad de 275cP, un pH de 5,1 y con 0,291% de ácido láctico. La fórmula artesanal a base de lactosuero fue de agrado para 41 niños que participaron en el análisis sensorial. Se recomienda su uso en niños que se encuentren en condición de vulnerabilidad nutricional.

Abstract The main objective of this research was to develop an artisan formula based on whey as food supplement directed to preschool children. It was a descriptive study carried out in three phases: 1. Preliminary tests, for the determination of the technological scheme; 2. Physical-chemical evaluation, for the characterisation of the product and determination of nutrients and, 3. Sensory evaluation: the level of satisfaction of the final product measured. The data obtained from the analysis were tabulated in four repetitions and analysed through descriptive statistics of central tendency and in frequencies expressed in tables and graphs using the statistical program SPSS version 20.0. As a result, for each 100 grams of dehydrated cottage cheese this malnuprovides: 480.28 kcal, 46.5% protein; 22.36% fat and 23.26% carbohydrates. The final formulation of the drink consisted of 2.9 g of dehydrated cottage cheese, 3.6 g of previously cooked rice and 1.8 g of diluted sugar for each prepared ounce. It was determined as a hypocaloric-hyperproteic and isomolar formula, with a viscosity of 275cP, a pH of 5.1 and with 0.291% lactic acid. The artisan formula based on whey was liked by 41 children who participated in the sensory analysis. As a conclusion, it can be recommended as food supplement in children with nutritional vulnerability conditions.

Resumo O objetivo principal desta pesquisa foi desenvolver uma fórmula artesanal à base de soro de leite como suplemento alimentar direcionado a crianças pré-escolares. Foi realizado um estudo descritivo em três fases: 1. Ensaios preliminares, para determinação do esquema tecnológico; 2. Avaliação físico-química, para caracterização do produto e determinação de macronutrientes e 3. Avaliação sensorial: mediu-se o grau de satisfação do produto final. Os dados obtidos das análises foram tabulados em quatro repetições e analisados por meio de estatísticas descritivas de tendência central e em frequências expressas em tabelas e gráficos utilizando o programa estatístico SPSS versão 20.0. Como resultado da análise proximal, para cada 100 gramas de requeijão desidratado fornece: 480,28 kcal, 46,5% de proteína; 22,36% de gordura e 23,26% de carboidratos. A formulação final da bebida consistiu em 2,9 g de requeijão desidratado, 3,6 g de arroz previamente cozido e 1,8 g de açúcar diluído para cada onça preparada. O resultado concluiu que é uma fórmula hipocalórica-hiperproteica e isoosmolar, com viscosidade de 275cP, pH de 5,1 e com 0,291% de ácido lático. A fórmula artesanal à base de soro de leite foi apreciada por 41 crianças que participaram da análise sensorial. É recomendado seu uso em crianças que se encontrem em condições de vulnerabilidade nutricional.

Novel biopharmaceutical development investigations towards drug and formulation performance optimization

For a drug to excerpt pharmacological action after oral intake, it first needs to be released from the formulation, get into solution (dissolve), be absorbed, and reach the systemic circulation. Since only solubilized drugs can be absorbed, and thus have therapeutic effect, the understanding of the dissolution and drug release processes of a drug product is of primary importance. Such understanding allows a robust formulation development with an ideal in vivo performance. In order to meet set standards, the performance assessment of oral drug products, such as dissolution testing, often applies conditions that are not reflective of the in vivo environment. The use of non-physiologically relevant dissolution method during the drug product development phase can be misleading and give poor mechanistic understanding of the in vivo dissolution process. Hence, we hypothesized that applying physiologically relevant conditions to the dissolution test would result in more accurate in vivo predictability for a robust and precise development process. Since the buffering system in the intestinal lumen operates at low molarity values, phosphate buffer at low buffer capacity was used as a first approach to an in vivo relevant parameter. Furthermore, a biphasic system was used, that is, the low buffer capacity medium was paired with an organic layer (n-octanol) to mimic the concurrent drug absorption that happens with the in vivo dissolution. Both poorly and highly soluble drugs in immediate release formulations (ibuprofen and metronidazole, respectively) were tested in this set-up to assess the dissolution in the aqueous medium and the partitioning to the organic phase. Additionally, enteric coated formulations were tested in bicarbonate buffer at the in vivo reported molarities values to assess the impact of buffer species on drug dissolution. The evaluated parameters were the buffer system (bicarbonate buffer vs. phosphate buffer), buffer capacity and medium pH. In all approaches, dissolution was also carried out in compendial buffer for comparison purposes. Our results demonstrate that the USP-recommended dissolution method greatly lacked discriminatory power, whereas low buffer capacity media discriminated between manufacturing methods. The use of an absorptive phase in the biphasic dissolution test assisted in controlling the medium pH due to the drug removal from the aqueous medium. Hence, the applied noncompendial methods were more discriminative to drug formulation differences and manufacturing methods than conventional dissolution conditions. In this study, it was demonstrated how biphasic dissolution and a low buffer capacity can be used to assess drug product performance differences. This can be a valuable approach during the early stages of drug product development for investigating drug release with improved physiological relevance. Similarly, all the enteric coated formulations displayed a fast release in phosphate buffer and complied with the compendial performance specifications. On the other hand, they all had a much slower drug release in bicarbonate buffer and failed the USP acceptance criteria. Also, the nature of the drug (acid vs base) impacted the dissolution behavior in bicarbonate buffer. This study indicates that compendial dissolution test for enteric coated tablets lacks physiological relevance and it needs to be reevaluated. Thus, an in vivo relevant performance method for EC products is needed. Overall, the findings of this thesis comprehensively demonstrates that meaningful differences in performance and accordance to clinical reports were only obtained when physiological relevant conditions were applied. Hence, our results indicate that the central hypothesis was answered positively

Para que um medicamento exerça a ação farmacológica após a ingestão oral, ele primeiro precisa ser liberado da formulação, dissolver, ser absorvido e atingir a circulação sistêmica. Uma vez que apenas medicamentos solubilizados podem ser absorvidos e, assim, ter efeito terapêutico, a compreensão dos processos de dissolução e liberação de um medicamento é de extrema importância. Tal compreensão permite o desenvolvimento de uma formulação robusta com o desempenho in vivo ideal. Para atender aos padrões regulatórios previamente estabelecidos, a avaliação da performance de formulações orais, como por exemplo, o teste de dissolução, frequentemente aplica condições que não refletem o ambiente fisiológico. O uso de métodos de dissolução não fisiologicamente relevante durante a fase de desenvolvimento do medicamento pode gerar resultados equivocados sem uma compreensão mecanistica do processo de dissolução in vivo. Portanto, a hipótese desse trabalho é que a aplicação de condições fisiologicamente relevantes no teste de dissolução resultaria em uma predição mais precisa da dissolução in vivo para um processo de desenvolvimento robusto e preciso. Uma vez que o sistema tampão no lúmen intestinal possui baixa molaridade, o tampão fosfato com baixa capacidade tamponante foi usado como uma primeira abordagem como um meio de dissolução fisiologicamente relevante. Além disso, foi utilizado um sistema bifásico, ou seja, o meio de baixa capacidade tamponante combinado a uma fase orgânica (n-octanol) para imitar a absorção in vivo. Formulações de liberação imediata contendo fármacos de baixa e de alta solubilidade (ibuprofeno e metronidazol, respectivamente) foram testadas no sistema bifásico para avaliar a dissolução no meio aquoso e a partição para a fase orgânica. Ademais, formulações com revestimento entérico foram testadas em tampão bicarbonato nos valores de molaridades fisiológicos para avaliar o impacto da espécie tamponante na dissolução do fármaco. Os parâmetros avaliados foram o sistema tampão (tampão bicarbonato vs. tampão fosfato), capacidade tamponante e pH médio. Em todas as abordagens, a dissolução também foi realizada em tampão farmacopeico para fins de comparação. Nossos resultados demonstraram que o método de dissolução farmacopeico não foi discriminativo, enquanto o meio com menor capacidade tamponante diferenciou entre as formulações obtidas via granulação úmida ou compressão direta. Ademais, a utilização da fase orgânica no teste de dissolução bifásica auxiliou no controle do pH do meio aquoso. Portanto, os métodos não compendiais aplicados foram mais discriminativos do que as condições de dissolução convencionais. Neste estudo, foi demonstrado como a dissolução bifásica e uma baixa capacidade tamponante podem ser usadas para avaliar as diferenças na performance de formulações. Esta pode ser uma abordagem valiosa durante os estágios iniciais do desenvolvimento de medicamentos para investigar a liberação destes sob condições fisiologicamente relevantes. Da mesma forma, todas as formulações com revestimento entérico exibiram uma liberação rápida em tampão de fosfato e atenderam às especificações farmacopeicas. Entretanto, a liberação do fármaco foi muito mais lenta em tampão de bicarbonato e consequentemente não cumpriram com as especificações farmacopeicas. Além disso, a natureza do fármaco (ácido vs. base) impactou o comportamento de dissolução no tampão de bicarbonato. Este estudo indica que o teste de dissolução convencional para comprimidos de liberação retardada não possui relevância fisiológica e precisa ser reavaliado. Portanto, os resultados desta tese demonstram de forma abrangente que diferenças significativas na performance condizentes com relatórios clínicos foram obtidas apenas quando as condições fisiológicas relevantes foram aplicadas. Esses resultados indicam que a hipótese central foi respondida positivamente

Studies on the enzymatic specificity of diguanylate cyclases domains and the production of new second messengers / Estudos na especificidade enzimática de diguanilato ciclases e na produção de novos segundos mensageiros

In the first chapter, studies on substrate recognition and enzymatic activity of GGDEF domains are presented. Many proteins containing GGDEF domains are diguanylate cyclases (DGCs, EC 2.7.7.65), enzymes that catalyze the conversion of 2 GTP molecules into the second messenger c-di-GMP in prokaryotes. This molecule is primarily implicated in the transition between motile and sessile lifestyles, as well several other phenotypes. Redundancy and diversity of GGDEF domain sequences in many bacterial genomes raises the possibility that other enzymatic functions may yet be discovered. To test this hypothesis, i) the effect of point mutations on the structure and enzymatic activity of GGDEF domains is analyzed, ii) the enzymatic specificity of wild-type GGDEF domains from different proteins is also tested, and iii) when non-canonical products are detected, enzymatic models are studied to understand its preferential production. The principal results obtained from these studies are as follows. Seven mutants of the DGC PleD (a GGDEF containing-protein from Caulobacter crescentus) were constructed and the crystallographic structure of two of them was solved, showing that they are unlikely to bind the guanine moiety in its active site. Additionally, five mutants of XAC0610, another DGC from Xanthomonas citr, were constructed and their substrate specificities were evaluated. None of those mutants were able to use ATP as a substrate. Finally, seven different GGDEF domain-containing DGCs from different sources were expressed and purified and their enzymatic specificities were tested with several nucleotide triphosphates. One enzyme, GSU1658 from Geobacter sulfurreducens was particularly promiscuous and shown to produce c-di-GMP, c-di-AMP, c-di-IMP, c-di-2´dGMP, cGAMP, c-GIMP, and c-AIMP. Interestingly, XAC0610 was able to recognize 2´dGTP as substrate. Analysis of enzyme kinetics of XAC0610 in presence of 2´dGTP and/or GTP showed the preferential formation of the hybrid linear product pppGp2´dG. The second chapter present studies on cyanide metabolism in Bacillus with focus on the cyanide dihydratase of Bacillus safensis. Cyanide is widely used in industries due to its high affinity for metals. This same ability confers potent toxicity to this compound. Thus, industries must reduce the cyanide concentration from wastewater before its final disposal. Physical, chemical, and biological methods have been developed to achieve this goal, but knowledge about metabolic pathways and the biology of enzymes involved in cyanide degradation is still scarce. Here, the isolation of a Bacillus safensis strain from mine tailings in Peru is described. Classification of this strain was done through a comparative analysis of 132 core genomes of strains from the Bacillus pumilus group. Sequence analysis determined that a cyanide dihydratase (CynD, EC 3.5.5.1)) encoded in the genome of the isolated strain was likely the enzyme responsible for cyanide degradation. Confirmation of the cyanide degrading activity of CynD from this strain was achieved by cloning, expression and purification of the enzyme and its enzymatic characterization. CynD from this strain was active up to pH 9 and oligomerization patterns analyzed by SEC-MALS and electron microscopy showed that the enzyme forms large helical structures at pH 8 and smaller structures at higher pHs. Finally, we show that CynD expression is strongly induced in the presence of cyanide. The last two years of graduate studies were carried out in the context of the COVID-19 pandemic. Thanks to the large amount of publicly available genomic data, we were able to carry out studies on the worldwide dynamics of the spread of SARS-CoV-2 mutants forms. In the first year of the pandemic, genomic classification of 171,461 genomes showed the presence of five major haplotypes based on nine mutations. The worldwide distribution and the temporal evolution of frequency of these haplotypes was carefully analyzed. All the haplotypes were identified in the six regions analyzed (South America, North America, Europe, Asia, Africa, and Oceania); however, the frequency of each of them was different in each of these regions. As of September 30, 2020, haplotype 3 (or operational taxonomic unit 3, OTU_3) was the most prevalent in four regions (South America, Asia, Africa, and Oceania). OTU_5 was the most prevalent in North America and OTU_2 in Europe. Temporal dynamics of the haplotypes showed that OTU_1 became nearly extinct after 8 months of pandemic (November 2020). Other OTUs are still present in different frequencies all around the world, while currently generating new variants. Based on their temporal dynamics, a classification scheme of 115 SARS-CoV-2 mutations identified from 1,058,020 SARS-COV-2 genomes was also performed. Three types of temporal dynamics of mutations were identified: i) High-Frequency mutations are characterized by a rapid increase in frequency upon its appearance, ii) medium and iii) low-frequency mutations maintain mid or low-frequencies for several months and can be region-specific. Finally, we performed a correlation analysis of the effective reproduction number (Rt) of SARS-CoV-2 harboring the high-frequency mutation N501Y with the level of control measures adopted in specific jurisdictions. We show that Rt is negatively correlated with the level of control measures in eight of the nine countries analyzed. This negative correlation was similar when we analyzed the Rt of SARS-CoV-2 not-harboring N501Y. Thus, the control measures likely diminish the Rt of both SARSCoV-2 wild-type and N501Y

O presente trabalho está dividido em três capítulos sobre linhas de pesquisa diferentes desenvolvidas pelo autor durante o período de doutorado No primeiro capítulo, são apresentados estudos relacionados ao reconhecimento estrutural de substratos e análise enzimática de domínios GGDEF com atividade diguanilato ciclase (EC 2.7.7.65). As proteínas contendo domínios GGDEF estão relacionados à produção enzimática do segundo mensageiro c-di-GMP, a partir de duas moléculas de GTP, em procariotos. Esta molécula está principalmente envolvida na transição entre os estilos de vida móveis e sésseis, bem como vários outros fenótipos. Redundância e diversidade de sequências de domínio GGDEF aumentam a possibilidade de que outras funções enzimáticas ainda possam ser descobertas. Para testar esta hipótese, i) o efeito de mutações pontuais na estrutura e atividade enzimática dos domínios GGDEF é analisado, ii) a especificidade enzimática de domínios GGDEF de enzimas diferentes também é testada e iii) quando produtos não canônicos são detectados, modelos enzimáticos são estudados para entender sua produção preferencial. Como resultados mais importantes, sete mutantes do PleD (uma proteína contendo GGDEF) foram construídos e a estrutura cristalográfica de dois delas foi resolvida, mostrando que é improvável que eles liguem à porção guanina em seu sítio ativo. Além disso, cinco mutantes da proteína XAC0610 de Xanthomonas citri foram construídos e sua capacidade de usar ATP ou GTP como substrato foi avaliada. Nenhum desses mutantes foi capaz de usar ATP como substrato. Finalmente, sete outras proteínas contendo GGDEF foram purificadas e sua especificidade enzimática foi avaliada com vários trifosfatos de nucleotídeos. Uma enzima promíscua chamada GSU1658 mostrou produzir c-di-GMP, c-di-AMP, c-di-IMP, c-di-2´dGMP, c-GAMP, cGIMP e c-AIMP. Curiosamente, o XAC0610 foi capaz de reconhecer 2´dGTP como substrato. A análise da cinética enzimática de XAC0610 na presença de 2´dGTP e GTP mostrou a formação preferencial do produto linear híbrido pppGp2´dG. O segundo capítulo aborda estudos sobre o metabolismo do cianeto em Bacillus com foco na cianeto dihidratase de Bacillus safensis. O cianeto é amplamente utilizado nas indústrias devido à sua alta afinidade com os metais. Esta mesma capacidade confere toxicidade potente a este composto. Assim, as indústrias têm que reduzir a concentração de cianeto das águas residuais antes de sua disposição final. Métodos físicos, químicos e biológicos têm sido desenvolvidos para atingir esse objetivo, mas o conhecimento sobre as vias metabólicas e a biologia das enzimas envolvidas na degradação do cianeto ainda é escasso. Aqui, é descrito o isolamento de uma cepa de Bacillus safensis de rejeitos de minas no Peru. A classificação desta cepa foi feita através de uma análise comparativa de 132 core genomes de cepas do grupo de Bacillus pumilus. Em seguida, determinamos que uma cianeto dihidratase (CynD, EC 3.5.5.1) codificada no genoma da cepa isolada era provavelmente a enzima responsável pela degradação do cianeto. A confirmação da atividade degradante de cianeto de CynD desta cepa foi feita por clonagem, expressão e purificação da enzima e realização de caracterização enzimática. O CynD desta cepa é ativo até pH 9 e os padrões de oligomerização analisados por SEC-MALS mostraram que a enzima forma longas estruturas helicoidais em pH 8 e estruturas menores enquanto o pH aumenta. Finalmente, foi demonstrado que a expressão de CynD é fortemente induzida na presença de cianeto. Os últimos dois anos do doutorado foram realizados no contexto da pandemia COVID- 19. Vários laboratórios se dedicaram a gerar conhecimento para ajudar no combate à pandemia. Nesta situação e graças à grande quantidade de dados genômicos disponíveis publicamente, estudos sobre a dinâmica das mutações do SARS-CoV-2 foram realizados. No primeiro ano da pandemia, a classificação genômica de 171.461 genomas mostrou a presença de cinco haplótipos principais com base em nove mutações. A distribuição mundial e a mudança de frequência desses haplótipos foram analisadas cuidadosamente. Todos os haplótipos foram identificados nas seis regiões analisadas (América do Sul, América do Norte, Europa, Ásia, África e Oceania); no entanto, a frequência de cada um deles foi diferente em cada uma dessas regiões. Em 30 de setembro de 2020, o haplótipo 3 (ou unidade taxonômica operacional 3, OTU_3) era o mais prevalente em quatro regiões (América do Sul, Ásia, África e Oceania). OTU_5 foi o mais prevalente na América do Norte e OTU_2 na Europa. A dinâmica temporal dos haplótipos mostrou que OTU_1 parece perto da extinção após 8 meses de pandemia (novembro de 2020). Outros OTUs ainda estão presentes em diferentes frequências em todo o mundo, mesmo atualmente gerando novas variantes. Com base em sua dinâmica temporal, um esquema de classificação de 115 mutações SARS-CoV-2 identificadas a partir de 1.058.020 genomas SARS-COV-2 também foi feito. Três tipos de dinâmica temporal de mutações foram identificados: i) Mutações de alta frequência, ii) mutações de média frequência e iii) mutações de baixa frequência. Finalmente, foi analisada a correlação do número de reprodução efetiva (Rt) do SARS-CoV-2 que contém a mutação de alta frequência N501Y com o nível de medidas de controle, mostrando que seu Rt está negativamente correlacionado com o nível de medidas de controle em oito dos nove países analisados. Esta correlação negativa foi semelhante quando foi analisado o Rt de SARS-CoV-2 sem a mutação N501Y. Assim, as medidas de controle provavelmente diminuirão o Rt de SARS-CoV-2 tipo selvagem e N501Y

Cariogenic and erosive potential of pediatric medicines and vitamin supplements / Potencial cariogênico e erosivo de medicamentos e suplementos vitamínicos pediátricos

Introduction: Pharmaceutical pediatric formulations with low in pH and high in total titratable acidicity used frequently and over long periods of time, have the potential to produce erosive lesions in teeth. On the other hand, high concentration of sucrose, the nocturnal use and the lack of hygiene after its administration, are some factors that can contribute to the cariogenic potential of these formulations. Objective: To evaluate in vitro the cariogenic and erosive potential of medicines and liquid vitamins and mineral supplements for pediatric use. Material and method: Medicines (n=41) and liquid vitamins and mineral supplements (n=12) childish were selected and analyzed for their physicochemical properties, pH, total titratable acidity (TTA) and total soluble solids concentration (TSS/°Brix). The package inserts and labels were analyzed to identify the composition regarding the content of sugars and acidulants, in addition to the side effects related to salivary flow. Result: The pH analysis indicated that there was greater variation in the observed averages in the medication group. As for the TTA at pH 5.5, supplements and medicines groups showed significant variation between the means found (p<0.05). The TTA results at pH 7.0 showed that the highest mean found was in the class of antihistamines and the lowest in the class of drugs that contain the association of antitussives and antihistamines. The analyses TSS demonstrated that across all drug classes and supplements the amount of TSS varied significantly (p<0.05) in all classes of medicines and supplements. Conclusion: Most medicines and pediatric liquid vitamin and mineral supplements demonstrated significantly different behaviors within the group itself regarding the variables analyzed that constitute risk factors for the development of dental caries and erosion.

Introdução: Formulações farmacêuticas pediátricas com baixo pH e alta acidez titulável usadas com frequência e por longos períodos de tempo têm potencial para produzir lesões erosivas nos dentes. Por outro lado, alta concentração de sacarose, uso noturno e falta de higiene bucal após a administração são fatores que podem contribuir para o potencial cariogênico dessas formulações. Objetivo: Avaliar in vitro o potencial cariogênico e erosivo de medicamentos e suplementos vitamínicos e minerais líquidos de uso pediátrico. Material e método: Medicamentos (n=41) e suplementos vitamínicos e minerais (n=12) líquidos infantis foram selecionados e analisados quanto às suas propriedades físico-químicas, pH, acidez total titulável (ATT) e concentração de sólidos solúveis totais (SST/°Brix). Bulas e rótulos foram analisados para a identificação do conteúdo em açúcares e acidulantes, além dos efeitos colaterais relacionados ao fluxo salivar. Resultado: A análise do pH indicou que no grupo medicamentos houve maior variação nas médias observadas. Quanto à ATT em pH 5,5, os grupos medicamentos e suplementos apresentaram variação significativa entre as médias (p<0,05). Os resultados da ATT em pH 7,0 demonstraram que a maior média encontrada foi na classe dos anti-histamínicos e a menor na classe dos medicamentos que contém a associação de antitussígenos e anti-histamínicos. A análise de SST demonstrou que em todas as classes de medicamentos e nos suplementos a quantidade de SST variou significativamente (p<0,05). Conclusão: Os medicamentos e suplementos vitamínicos e minerais líquidos apresentaram comportamentos diferentes dentro do mesmo grupo quanto às variáveis analisadas, apresentando potencial cariogênico e erosivo em sua maioria.

Stability indicating Rp-UPLC method development and validation for the simultaneous estimation of fosnetupitant and palonosetron in bulk and injection dosage form

Abstract A stability indicating UPLC method has been developed and validated for the simultaneous determination of fosnetupitant and palonosetron in bulk and in injection dosage form. This combination is used for the prevention of acute and delayed nausea and vomiting associated with initial and repeated courses of highly emetogenic chemotherapy for cancer. The chromatographic analysis was performed on an HSS, RP C18 column (2.1 x 100 mm, 1.8 µm) with an isocratic mobile phase composed of 0.25 M potassium dihydrogen orthophosphate buffer (pH 6.5), pH adjusted with dilute sodium hydroxide:acetonitrile (55:45 v/v), at a flow rate of 0.5 mL/min, and the eluents were monitored at an isosbestic point of 286 nm. The developed method was validated according to the ICH guidelines pertaining to specificity, precision, accuracy, linearity and robustness, and the stability indicating nature of the method was established by forced degradation studies. The retention times of fosnetupitant and palonosetron were observed at 1.390 and 2.404 min, respectively. The developed method proved to be accurate and precise. Linearity was established between 4.70 and 14.10 µg/mL for fosnetupitant and between 0.05 and 0.15 µg/mL for palonosetron. The LOD and LOQ were 0.115 and 0.385 µg/mL, respectively, for fosnetupitant, and 0.005 and 0.016 µg/mL, respectively, for palonosetron. Therefore, the proposed UPLC method was reliable, reproducible, precise and sensitive for the quantification of fosnetupitant and palonosetron.

Development of novel mucoadhesive gels containing nanoparticle for buccal administration of dexamethasone

Abstract This study aimed to develop promising and innovative mucoadhesive gel systems containing dexamethasone-loaded nanoparticle to increase the effectiveness of treatment for oral precancerous lesions and to reduce side effects. In this respect, a dexamethasone-loaded nanoparticle formulation was prepared by using emulsification/solvent evaporation method. The nanoparticle has high zeta potential (-10.3±0.5 mV), low particle size (218.42±2.1), low polydispersity index (0.070±0.014) and high encapsulation efficiency (95.018±2.982%). To improve the mucosal retention time, the dexamethasone-loaded nanoparticle was dispersed in mucoadhesive gel using gellan gum. The developed gels offered appropriate pH value, high drug content, suitable mechanical and mucoadhesive performance and appropriate viscosity for mucosal administration. All formulations exhibited plastic flow and typical gel-type mechanical spectra after the determined frequency value. The developed formulations exhibited extended drug release as intended for these systems. Cytotoxicity was tested by MTT assay in human epithelioid carcinoma cell (HeLa) in vitro. The MTT assay showed that the blank formulations were non-toxic to cells. It was observed that the bioactivity of the free dexamethasone was potentiated by mucoadhesive gels containing dexamethasone-loaded nanoparticle in HeLa cells. Results from this study indicate that mucoadhesive gels are effective for the local treatment of precancerous lesions. Our findings showed that the developed formulations were worthy of further studies.

New topical microemulsions of etofenamate as sufficient management of osteoarthritis

Abstract In this study, microemulsions containing etofenamate were prepared and evaluated as dermal delivery carriers. The developed microemulsions consist of oleic acid, Span 80, Tween 20, Cremophor EL, Transcutol and ethanol. The percentage of etofenamate loading in the microemulsions was 5% (w/w). The characterization of formulations included droplet size, zeta potential, pH, conductivity, PDI, refractive index and viscosity. Moreover, ex vivo penetration study was carried out using mice abdominal skin. The developed formulations were analyzed for their cytotoxicity via MTT assay and tested for their anti-inflammatory properties opposed to LPS-stimulated nitrite prοduction in RAW 264.7 cells. As ideal formulation, M2ETF, was chosen due to its greater permeation, lower penetration as well as higher anti-inflammatory

Selective Separation and Preconcentration of Caffeine from Natural and Pharmaceutical Products using New Polyurethane Foams

Abstract Two polyurethane foam-based sorbents (PUF) were synthesized by imprinting and grafting techniques and examined for selective separation and preconcentration of caffeine (CAF) in some pharmaceutical products and in black tea. Molecularly imprinted PUF was synthesized based on hydrogen-bonding interactions between CAF and alizarin yellow G (AYG) and subsequent polymerization into PUF. The static experiments indicated optimum sorption conditions at pH=6.5 and 5.5 for imprinted PUF (AY-IPUF) and grafted PUF (AY-GPUF), respectively. In the online experiments, the suitable preconcentration time was found to be 40 and 20s for (AY-IPUF) and (AY-GPUF), respectively, at a flow rate of 1.75 mL.min-1. Desorption of CAF has been affected by passing 500 µL of 0.05, 0.01 mol.L−1 HCl eluent onto (AY-IPUF) and (AY-GPUF), respectively. The online methods have provided satisfactory enrichment factors of 8.4 and 10.5 for (AY-IPUF) and (AY-GPUF), respectively. The time consumed for preconcentartion, elution and determination steps was 1.48 and 1.05 min, thus, the throughput was 42 and 57 h-1, for (AY-IPUF) and (AY-GPUF), respectively. The developed sorbents were studied for the determination of CAF in pharmaceutical samples which will be helpful to minimize caffeinism. Finally, in silico bioactivity, ADMET and drug-likeness predictive computational studies of caffeine were also carried out

Curcumin solid dispersion based on three model acrylic polymers: formulation and release properties

Abstract To investigate structure-property relationship of polymer-based curcumin solid dispersion (SD), three acrylic polymers were used to formulate curcumin SD by solvent evaporation method. Curcumin Eudragit EPO SD (cur@EPO), curcumin Eudragit RS PO SD (cur@RSPO) and curcumin Eudragit RL PO SD (cur@RLPO) showed deep red, golden orange and reddish orange color, respectively. Cur@RSPO entrapped 15.42 wt% of curcumin followed by cur@RL PO and cur@EPO. FTIR spectra indicated that in cur@EPO, curcumin may transfer hydrogen to the dimethylaminoethyl methacrylate group and thus change its color to red. In contrast, curcumin may form hydrogen bonding with Eudragit RS PO and Eudragit RL. Curcumin exists in amorphous state in three SDs as proved by differential scanning calorimetry and X-Ray diffraction measurement. In vitro digestion presented that lower pH value in simulated gastric fluid (SGF) stimulates the curcumin release from cur@EPO while permeability influences the release profile in other two SDs. When in simulated intestinal fluid (SIF), first order release model governs the release behaviors of all three SDs which showed sustained release pattern. Our results are helpful to elucidate how structure of polymer may impact on the major properties of curcumin contained SD and will be promising to broaden its therapeutic applications.

Bioprocess optimization of interferon ß-1-a in Pichia pastoris and its improved inhibitory effect against hepatocellular carcinoma cells

Interferon-ß-1a (INF-ß-1a) has gained significant attention due to its emerging applications in the treatment of different human diseases. Therefore, many researchers have attempted to produce it in large quantities and also in a biologically active form using different expression systems. In the present study, we aimed to improve the expression level of INF-ß-1a by Pichia pastoris using optimization of culture conditions. The codon-optimized INF-ß- 1a gene was cloned into pPICZαA plasmid under the control of alcohol oxidase I (AOX1) promoter. The protein expression was induced using different concentrations of methanol at different pHs and temperatures. The biological activity of produced protein was evaluated by anti-proliferative assay. The ideal culture conditions for the expression of INF-ß-1a by P. pastoris were found to be induction with 2% methanol at pH 7.0 culture medium at 30 C which yielded a concentration of 15.5 mg/L INF-ß-1a in a shake flask. Our results indicate that differences in glycosylation pattern could result in different biological activities as INF- ß-1a produced by P. pastoris could significantly more reduce the cell viability of HepG-2 cells, a hepatocellular carcinoma cell line, than a commercially available form of this protein produced by CHO

Semisolid formulations based on solid-in-oil-in-water systems containing proteins

Abstract In recent years, improvements have been made, through biotechnological processes, in the production and development of peptides capable of increasing collagen and elastin synthesis for anti-aging skin care. However, proteins have many limitations due to their structural, chemical and physical fragility to external aggressions, which may cause conformational changes, leading to loss of biological activity. Therefore, it is important to create delivery systems that protect these biomolecules from damage, allowing them to reach their target. This work aimed to develop a system able to carry bovine serum albumin (BSA), used as a model of a protein, and to incorporate this system in a semisolid formulation suitable for skin application. A microemulgel based on a solid-in-oil-in-water (S/O/W) microemulsion was prepared. Firstly, the association efficiency (AE) of lyophilized BSA-sucrose ester complex and the size of S/O nanodispersion were assessed; then, the characterization and stability evaluation of the final semisolid formulation through evaluation of pH, texture and rheological behavior were performed. The average value of AE was 54.74% ± 2.17. It was possible to develop an S/O/W microemulsion, which allowed the subsequent development of an S/O/W microemulgel that assured suitable pH, texture and rheological characteristics for skin application.

Characterization, Antioxidant and Antibacterial Potentials of Tamarindus indica L. Fruit Pulp Extract Loaded O/W Nanoemulsions

Abstract The main purposes of the current study were to formulate o/w nanoemulsions as a carrier for Tamarindus indica (tamarind) fruit pulp extract and to study the antioxidant and antibacterial potentials of nanoemulsions containing tamarind extract, focusing on cosmetic/hygiene applications. The o/w nanoemulsions using a mixture of Tween 80 and Span 80 as an emulsifier (5%w/w) were prepared by a high pressure homogenization process. Two concentrations of sweet tamarind extract, 3.3 and 6.6%w/w, based on the bioactivity study, were incorporated into the blank nanoemulsions to produce loaded nanoemulsions, F1-3.3TE (3.3%) and F1- 6.6TE (6.6%). As compared with the unloaded nanoemulsion, both tamarind extract loaded nanoemulsions showed reduced pH and significantly increased viscosity. Overall, the loaded nanoemulsions had droplet sizes of approximately 130 nm, zeta potential around -38 mV and polydispersity index (PDI) values less than 0.2. The nanoemulsion F1-3.3TE had better stability (e.g. significantly greater % tartaric acid content and lesser PDI value) than the nanoemulsion F1-6.6TE did. The antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl assay revealed that the nanoemulsions F1-3.3TE and F1-6.6TE had scavenging activities of 81.66 ± 0.77% and 63.80 ± 0.79%, respectively. However, antioxidant activity of these two formulations decreased under stress conditions (heating-cooling cycles). Such incidence did not occur for their antibacterial properties investigated by agar well diffusion technique. The two formulations exhibited inhibition zones of approximately 24.0-27.7 mm against Staphylococcus aureus and Staphylococcus epidermidis, responsible for malodor of underarms. The results suggest the potential of using sweet tamarind pulp extract loaded nanoemulsions as hygiene products.

Geohelmintos y parámetros fisicoquímicos del suelo como indicadores de calidad ambiental en el distrito de José Crespo y Castillo, Huánuco / Geohelminths and physicochemical parameters of the soil as indicators of environmental quality in José Crespo y Castillo, Huánuco district

En la investigación se determinaron la presencia de geohelmintos y se evaluó la calidad ambiental del suelo mediante parámetros fisicoquímicos en el distrito de José Crespo y Castillo ­ Huánuco, Perú. Se detectaron y cuantificaron los geohelmintos, se caracterizó los perfiles modales y propiedades fisicoquímicas en función del Soil Taxonomy, y contraste con el estándar de calidad para el cadmio (Cd) y determinación del índice de calidad ambiental del suelo empleando el análisis de componentes principales. Los perfiles modales son Fluventic Eutrudepts, Lithic Udorthents, Typic Dystrudepts, Typic Dystrudepts - Lithic Udorthents, Typic Dystrudepts - Typic Endoaquents, Typic Endoaquents, Typic Eutrudepts - Typic Eutrudepts, Typic Udifluvents y Typic Udorthents; los parámetros fisicoquímicos textura, pH, materia orgánica, nitrógeno, fosforo disponible, potasio disponible, cadmio disponible, capacidad de intercambio catiónico efectivo, calcio, magnesio, aluminio, hidrogeno, bases y ácidos cambiables y porcentaje de saturación de aluminio, determinando que el cadmio disponible se encuentra dentro de los estándares de calidad ambiental del Perú; y el índice de calidad ambiental del suelo es de 41,48%, teniendo la calificación de un suelo regular de calidad ambiental. Y la contaminación por Ascaris lumbricoides fue en 25 de las calicatas (55,56%), presente en los 8 tipos de suelos catalogados, seguida de las unicinarias representadas por Necator americano y Ancylostoma duodenale en 14 calicatas (31,11%) de pH ligeramente a medianamente acido, y Taenias y Capilaria, ambos en el 8,29%; los geohelmintos como riesgo de salud pública, permanecen por largo de tiempo en el suelo, independientemente de la calidad y en amplios rangos de pH, favorecidos por niveles de sustratos orgánicos derivados de la antropogénesis(AU)

In the investigation, the presence of geohelminths was determined and the environmental quality of the soil was evaluated through physicochemical parameters in the district of José Crespo y Castillo - Huánuco, Peru. Geohelminths were detected and quantified and the modal profiles and physicochemical properties were characterized based on the Soil Taxonomy, and contrast with the quality standard for cadmium (Cd) and determination of the environmental quality index of the soil using the main component analysis. Modal profiles are Fluventic Eutrudepts, Lithic Udorthents, Typic Dystrudepts, Typic Dystrudepts - Lithic Udorthents, Typic Dystrudepts - Typic Endoaquents, Typic Endoaquents, Typic Eutrudepts - Typic Eutrudepts, Typic Udifluvents, and Typic Udorthents; the physicochemical parameters texture, pH, organic matter, nitrogen, available phosphorus, available potassium, available cadmium, effective cation exchange capacity, calcium, magnesium, aluminium, hydrogen, exchangeable bases and acids and percentage of aluminum saturation, determining that cadmium available is within the environmental quality standards of Peru; and the environmental quality index of the soil is 41.48%, having the qualification of a regular soil of environmental quality. And the contamination by Ascaris lumbricoides was in 25 of the pits (55.56%), present in the 8 types of cataloged soils, followed by the unicinarias represented by Necator americano and Ancylostoma duodenale in 14 pits (31.11%) of pH slightly to medium acid, and Taenias and Capilaria, both at 8.29%; As a public health risk, geohelminths remain in the soil for a long time, regardless of quality and in wide pH ranges, favored by levels of organic substrates derived from anthropogenesis(AU)

Obtainment and characterization of digestive aspartic proteases from the fish Caranx hippos (Linnaeus, 1766) / Obtenção e caracterização de proteases aspárticas digestórias do peixe Caranx hippos (Linnaeus, 1766)

This work aimed to obtain aspartic proteases of industrial and biotechnological interest from the stomach of the crevalle jack fish (Caranx hippos). In order to do so, a crude extract (CE) of the stomach was obtained and subjected to a partial purification by salting-out, which resulted in the enzyme extract (EE) obtainment. EE proteases were characterized physicochemically and by means of zymogram. In addition, the effect of chemical agents on their activity was also assessed. By means of salting-out it was possible to obtain a purification of 1.6 times with a yield of 49.4%. Two acid proteases present in the EE were observed in zymogram. The optimum temperature and thermal stability for EE acidic proteases were 55 ºC and 45 °C, respectively. The optimum pH and pH stability found for these enzymes were pH 1.5 and 7.0, respectively. Total inhibition of EE acid proteolytic activity was observed in the presence of pepstatin A. dithiothreitol (DTT) and Ca2+ did not promote a significant effect on enzyme activity. In the presence of heavy metals, such as Al3+, Cd2+ and Hg2+, EE acidic proteases showed more than 70% of their enzymatic activity. The results show that it is possible to obtain, from the stomach of C. hippos, aspartic proteases with high proteolytic activity and characteristics that demonstrate potential for industrial and biotechnological applications.

Este trabalho objetivou obter proteases aspárticas de interesse industrial e biotecnológico a partir do estômago do peixe xaréu (Caranx hippos). Para isso, foi obtido um extrato bruto do estômago, o qual foi submetido a uma purificação parcial por salting-out onde se obteve o extrato enzimático (EE). As proteases do EE foram caracterizadas físico-quimicamente e através de zimograma. Além disso, o efeito de agentes químicos sobre sua atividade também foi avaliado. Através de salting-out foi possível obter uma purificação de 1,6 vezes com rendimento de 49,4%. Foram observadas duas proteases ácidas presentes no EE através de zimograma. A temperatura ótima e a estabilidade térmica para as proteases ácidas do EE foram de 55 ºC e 45 °C, respectivamente. O pH ótimo e a estabilidade ao pH encontrados para estas enzimas foram o pH 1,5 e 7,0, respectivamente. Observou-se a inibição total da atividade proteolítica ácida do EE na presença de pepstatina A. O ditiotreitol (DTT) e o Ca2+ não promoveram efeito significativo na atividade enzimática. Na presença de metais pesados, como Al3+, Cd2+ e Hg2+, o EE manteve mais de 70% de atividade enzimática do EE. Os resultados mostram que é possível obter, a partir do estômago de C. hippos, proteases aspárticas com alta atividade proteolítica e características que demonstram potencial para aplicações industriais e biotecnológicas.

Recent progress in magnetic nanoparticles and mesoporous materials for enzyme immobilization: an update / Progresso recente em nanopartículas magnéticas e materiais mesoporosos para imobilização de enzimas: uma atualização

Enzymes immobilized onto substrates with excellent selectivity and activity show a high stability and can withstand extreme experimental conditions, and their performance has been shown to be retained after repeated uses. Applications of immobilized enzymes in various fields benefit from their unique characteristics. Common methods, including adsorption, encapsulation, covalent attachment and crosslinking, and other emerging approaches (e.g., MOFs) of enzyme immobilization have been developed mostly in recent years. In accordance with these immobilization methods, the present review elaborates the application of magnetic separable nanoparticles and functionalized SBA-15 and MCM-41 mesoporous materials used in the immobilization of enzymes.

Enzimas imobilizadas em substratos com excelente seletividade e atividade apresentam alta estabilidade e podem suportar condições experimentais extremas, e seu desempenho foi mantido após repetidos usos. As aplicações de enzimas imobilizadas em vários campos se beneficiam de suas características únicas. Métodos comuns, incluindo adsorção, encapsulamento, ligação covalente e reticulação, e outras abordagens emergentes (por exemplo, MOFs) de imobilização de enzima, foram desenvolvidos principalmente nos últimos anos. De acordo com esses métodos de imobilização, a presente revisão elabora a aplicação de nanopartículas magnéticas separáveis e materiais mesoporosos funcionalizados SBA-15 e MCM-41 usados na imobilização de enzimas.

Carangoides bartholomaei (Cuvier, 1833) stomach: a source of aspartic proteases for industrial and biotechnological applications / Estômago de Carangoides bartholomaei (Cuvier, 1833): uma fonte de proteases aspárticas para aplicações industriais e biotecnológicas

The viscera and other residues from fish processing are commonly discarded by the fishing industry. These byproducts can be a source of digestive enzymes with industrial and biotechnological potential. In this study, we aimed at the extraction, characterization, and application of acidic proteases from the stomach of Carangoides bartholomaei (Cuvier, 1833). A crude extract from the stomachs was obtained and submitted to a partial purification process by salting-out, which obtained a Purified Extract (PE) with a specific proteolytic activity of 54.0 U·mg-1. A purification of 1.9 fold and a yield of 41% were obtained. The PE presents two isoforms of acidic proteases and a maximum proteolytic activity at 45 °C and pH 2.0. The PE acidic proteolytic activity was stable in the pH range of 1.5 to 7.0 and temperature from 25 °C to 50 °C. Purified Extract kept 35% of its proteolytic activity at the presence of NaCl 15% (m/v) but was totally inhibited by pepstatin A. Purified Extract aspartic proteases presented high activity in the presence of heavy metals such as Cd2+, Hg2+, Pb2+, Al3+, and Cu2+. The utilization of PE as an enzymatic addictive in the collagen extraction from Nile tilapia scales has doubled the process yield. The results indicate the potential of these aspartic proteases for industrial and biotechnological applications.

As vísceras e outros resíduos do processamento de peixes são geralmente descartados pela indústria pesqueira. Esses resíduos podem ser uma fonte de enzimas digestivas com potencial industrial e biotecnológico. Neste estudo, objetivamos a extração, caracterização e aplicação de proteases aspárticas do estômago de Carangoides bartholomaei (Cuvier, 1833). Um extrato bruto do estômago foi obtido e submetido a um processo de purificação parcial, que obteve um Extrato Purificado (EP) com uma atividade proteolítica específica de 54,0 U·mg-1. Foi obtida uma purificação de 1,9 vezes e um rendimento de 41%. O EP apresenta duas isoformas de proteases ácidas e atividade proteolítica máxima a 45 °C e pH 2,0. A atividade proteolítica do EP foi estável na faixa de pH de 1,5 a 7,0 e temperatura de 25 °C a 50 °C. O EP manteve 35% de sua atividade proteolítica na presença de NaCl a 15% (m/v), mas foi totalmente inibida pela pepstatina A. As proteases ácidas do EP apresentaram alta atividade na presença de metais pesados como o Cd2+, Hg2+, Pb2+, Al3+ e Cu2+. A utilização de EP como aditivo enzimático na extração de colágeno a partir de escamas de tilápia do Nilo dobrou o rendimento do processo. Os resultados indicam um potencial dessas proteases para aplicações industriais e biotecnológicas.