Navegando por Assunto "Hydrolysis"

Agora exibindo 1 - 4 de 4

Acesso aberto (Open Access)
Estudo da hidrólise enzimática do caroço de açaí (euterpe oleraceae mart) para a produção de etanol
(Universidade Federal do Pará, 2016-08-31) CORDEIRO, Márcio de Andrade; MACHADO, Nelio Teixeira; http://lattes.cnpq.br/5698208558551065; ALMEIDA, Ossalin; http://lattes.cnpq.br/7040173036131516; https://orcid.org/0000-0003-3895-0952
The use of Acai seed (Euterpe oleracea Mart), for energy purposes has been little studied, therefore we sought in this work to study the production of second generation ethanol from enzymatic hydrolysis of core açai in natura and treated with solvent two temperature conditions (60 to 70 °C). The enzyme β-glucosidase used in this study as technical specifications (Table 5). The Açai core samples, passed through washing, drying at ambient temperature, in an oven with air circulation at 105 ± 5 °C until constant weight, grinding and solvent treatment. The moisture content and the yield on a wet basis of acai core "in natura" was 39.59 and 60.41%. Morphological analysis by scanning electron microscopy (SEM), allowed to analyze the structure and the presence of chemical elements (C, O, Si and Al) in the core and fiber. The -ethanoic acid extract of acai seed showed satisfactory capacity (82%) to scavenge free radicals (antioxidant activity), against free radical DPPH. As a result of the enzymatic hydrolysis process, the core acai without treatment (CANT60) proved to be a promising lignocellulosic biomass to obtain second generation ethanol, it contains a high cellulose content (40.29%), besides presenting good income in the release of glucose (13.687 g L-1) after enzymatic hydrolysis. The average ash content for CANT and CAT were 0.15 and 0.13%. Treatment with acai core of the solvent in the conversion of cellulose into glucose, the yield was below 25%, in both temperature conditions (60 to 70 °C), it was not able to disrupt the plant wall biomass in particular cellulose, hemicellulose and lignin, making fermentable sugars available on the enzymatic hydrolysis process, because of possible inhibitors generated during the treatment. By analyzing the experimental data, we can say that the best condition of enzymatic hydrolysis of acai core was CANT60 and glucose obtained by enzymatic hydrolysis of acai seed was well assimilated by the yeast Saccharomyces cerevisiae for ethanol production.
Acesso aberto (Open Access)
Estudo de misturas de enzimas (complexo celulásico, complexo enzimático, xilanase, β-glucanase e xilanase, β-glucosidase e Glucoamilase) na bioconversão do bagaço da cana-de-açúcar em etanol
(Universidade Federal do Pará, 2015) MOREIRA, Rosiane Fernandes; MACHADO, Nelio Teixeira; http://lattes.cnpq.br/5698208558551065
This work, it was proposed to evaluate mixtures of commercial enzymes by supplier Novozymes A / S. The enzymes used in this work were: celulase complex, xylanase, β-glucosidase, enzymático complex, xylanase and β-glucanase and glucoamylase in the glucose production from sugarcane bagasse subjected to treatment with alkali hydroxide solution sodium at room temperature, 70 ° C, 90 ° C and 120 ° C. The BCA yield on a dry basis after treatment with NaOH solution 6 (w / v) were 30.64% ± 1.395 (PACTA), 44.00% ± 1.787 (PAC70), 65.91% ± 1.096 (PAC90), and 95.25% ± 1.461 (CAP 120), respectively. The ash content for the BCA were 2.05% ± 0.027 (PACTA), 0.62% ± 0.013 (PAC70), 0.48% ± 0.007 (PAC90) and 0.18% ± 0.008 (PAC120). The lignin contents were 20.67 ± 0.603 (PACTA), 13.03 ± 0.711 (PAC70), 6.05 ± 0.196 (PAC90) and 5.49 ± 0.151 (PAC120). The results suggest that the conversion rates of cellulosic waste into glucose are strongly dependent on temperature in the alkaline pulping process. The kinetic parameters obtained in kinetic adjustments enzymatic hydrolysis of the BCA for PACTA, PAC70, PAC90 and PAC120 were: Vmax (g/h) equal to 7.20; 5.12; 4.54 and 0.87 respectively; Km (g) equal to 3.6; 2.56; 2.27 and 2.56 respectively; Kcat (h) equal to 1.44; 1.02; 0.91 and 0.17 respectively; Km/Vmax equal to 0.5 for all samples and Kcat/Km of 0.4 for all samples.
Acesso aberto (Open Access)
Hidrólise da quitosana: obtenção de um extrato enzimático e caracterização do produto hidrolisado
(Universidade Federal do Pará, 2022-08-09) GONÇALVES, Cleidiane Gonçalves e; FERREIRA, Nelson Rosa; http://lattes.cnpq.br/3482762086356570; https://orcid.org/0000-0001-6821-6199; LOURENÇO, Lúcia de Fátima Henriques; http://lattes.cnpq.br/7365554949786769; https://orcid.org/0000-0001-5009-8235
Chitin, extensively found in crustaceans exoskeletons, insects, and microorganisms, has limited usage due to its low solubility in aqueous solution, requiring its partial deacetylation to obtain chitosan. Chitosan's depolymerization has attracted considerable attention, as its oligomers have high water solubility, biocompatibility, and non-toxicity, as well as beneficial properties such as antimicrobial, antioxidant, and antitumor properties. For this reason, in this research, a review article was produced (Chapter I) based on the main methods of chitosan hydrolysis, besides analyzing the parameters that influence the acquisition, and characteristics of hydrolysis results, effectively and at a lower cost. Among the approaches studied, enzymatic hydrolysis excels due to its control ease and performance under milder conditions, making it possible to use low-cost enzymes belonging to the glycoside hydrolases group. Thus, enzymatic hydrolysis was defined as a technique for various sizes of chitosan acquisition (Chapter II) through the production of an enzymatic extract (integral enzymatic extract - IEE) from a filamentous fungus strain. The enzyme identification present in the IEE showed exo-chitinases, endo-chitinase, and cellobiohydrolase. Considering the same reaction conditions, the IEE showed greater efficiency than the commercial enzyme (Celluclast 1.5 L®), which was used as a parameter because it is an enzyme capable of cleaving the β-1,4-glycosidic bond of chitosan - similar to chitosanase, besides presenting a lower cost. The IEE reduced the molecular weight of chitosan by 47.80; 75.24 and 93.26% at 2.0; 5.0, and 24 h, respectively. Through the FTIR analysis, a lower absorbance of the spectral signals of chitosan oligomers was detected, and the crystallinity reduced after 3.0 h of hydrolysis. Based on this study, we can infer that enzymatic hydrolysis, under established conditions, is effective at obtaining lower molecular weight chitosan using unpurified crude extract.
Acesso aberto (Open Access)
Obtenção de açúcares fermentescíveis a partir da casca de andiroba (carapa guianensis aubl.): estudo do pré-tratamento alcalino e avaliação cinética
(Universidade Federal do Pará, 2020-01-24) SOUZA, Leiliane do Socorro Sodré de; QUARESMA, João Nazareno Nonato; http://lattes.cnpq.br/7826389991864785; https://orcid.org/0000-0001-9365-7498
Neste trabalho, as cascas das sementes de andiroba foram submetidas a pré- tratamento alcalino, visando maximizar a recuperação dos açúcares redutores, avaliando o melhor desempenho de operação através das variáveis, tempo de reação (20, 60 e 100 min), concentração de NaOH (2, 3 e 4% (m/v)) e temperatura (60, 90 e 120ºC), em concentração de sólidos fixa, de 5% (m/v). Foi utilizado o planejamento experimental de Box-Behnken (15 ensaios). A biomassa pré-tratada nos 15 experimentos, foi hidrolisada enzimaticamente, em condições idênticas, carga de sólidos (5%), carga enzimática (15 FPU/g de biomassa) e tempo de reação (48 horas). O material lignocelulósico foi caracterizado através das análises de celulose (36,96 %), hemicelulose (16,74 %), lignina (36,02 %), extrativos (7,49 %), umidade (9,21 %), e cinzas (1,53 %). A otimização foi realizada por meio da abordagem metodologia de superfície de resposta. O modelo forneceu um coeficiente de determinação (R2) de 0,96, para sacarificação e 0,97, para sólidos recuperados. As condições ótimas previstas para realizar o processo foram, tempo de reação = 100 min, concentração de NaOH = 4% (m/v), temperatura = 120ºC, que permitiram obter uma conversão em termos de açúcares redutores de 47,89 %. O material lignocelulósico pré-tratado nas melhores condições, foi avaliado morfologicamente, através das análises de Espectroscopia no Infravermelho com Transformada de Fourier (FTIR) e Microscopia Eletrônica de Varredura (MEV), onde foi possível observar a maior disponibilidade da fração celulósica. Através do pré-tratamento alcalino foi possível reduzir em 34,7 % a fração de lignina, e em 23,52 % a fração de hemicelulose. A biomassa tratada nas melhores condições determinadas através da análise estatística foi hidrolisada e a cinética de sacarificação foi acompanhada. O processo foi acompanhado por um período de 96 horas, e foi possível observar que o rendimento de 54,44 % foi alcançado para um tempo de 72 horas, após esse período não houve mais aumento significativo. Os resíduos gerados na etapa de tratamento alcalino (licor negro) e hidrólise enzimática (biomassa residual), foram caracterizados através de FTIR e análise termogravimétrica, respectivamente, o que permitiu observar a presença predominante de lignina no licor negro, e de celulose na biomassa residual. Estes resultados podem ser considerados satisfatórios no contexto da biomassa florestal e pode ser elevado em uma escala futura do laboratório para a escala piloto, com estudos sobre a etapa de hidrólise enzimática.