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Estudo da imobilização de celulase em géis de quitosana
(Universidade Federal de São Carlos, 2007-01-29) Martins, Rafael Elias; Giordano, Raquel de Lima Camargo; https://lattes.cnpq.br/0792538389469353
Cellulases are enzymes that catalyze the hydrolysis of cellulose producing glucose. Immobilization and stabilization of these enzymes could improve enzymatic process making it more attractive by reducing costs during their use. In this work, Celluclast (Novozymes A/S, Denmark) and CG 200 (Genencor) were immobilized into chitosan and into a chitosan/alginate hybrid support, after activation of the support with glutaraldehyde and glycidol under different conditions of immobilization such as temperature and pH. Immobilization process was evaluated by calculating the immobilization yield, coupling yield and thermal stability at 65°C. Temperature and pH optimum of enzymatic activity were analyzed as well. The best derivatives were obtained with chitosan alginate activated with glycidol, after immobilization at 27°C, pH 7.0, for 16 hours. The biocatalyst presented 56.3% of immobilization yield, 40.6% of coupling yield and it 11.2 fold more stable than free enzyme at 65°C. The temperature and pH for maximum activity of the derivatives and soluble enzyme was 60°C and 50°C, pH 2.5-3.0 and 4.2, respectively. Finally, the performance of the best biocatalyst developed in this work in the hydrolysis of sugarcane bagasse was compared to one observed using soluble enzyme. Although a higher conversion has been obtained with soluble enzyme in the beginning of the reaction, the immobilized enzyme allowed to reach a higher final conversion, 70%, than the one obtained with free Celluclast, 38.9%.
Geração de pontos de casos de uso no ambiente Cocar
(Universidade Federal de São Carlos, 2007-01-29) Martins, Marcos Danilo Chiodi; Fabbri, Sandra Camargo Pinto Ferraz; https://lattes.cnpq.br/2204086299921323; https://lattes.cnpq.br/7984293538352464
The objective of this paper was to implement an initial version of a development support environment named COCAR based on the Use Case Model. Even though the conception and some features of this environment are the outcome of several other master papers, this work emphasises the relevance of the Use Case Point metric (PCU). This metric strengthens the usage of estimates which are of fundamental importance for the calculation of a system development time. Furthermore, such a metric is associated to one of the main drivers of a software product quality, which is the ability to meet delivery time. With the advent of the object oriented development paradigm, the Use Case Point metric based on the Use Case Model has been highlighted. However, given the lack of formality and standardization, specifying and building these models a PCU metric may be jeopardized. In the scope of this work, there have been relevant contributions to building such an environment implementing a technique called TUCCA which helps with the model standardization, a functionality that supports the insertion of system requirements in the environment and the generation of PCU as in the model generated by TUCCA application. In the assessment process of the COCAR environment an informal case study, in which a specification of actual software from a development company, has been carried out, producing Use Case Models, PCU s and effort estimates, both compared against the industry benchmarks. The results of this research showed that for this particular situation the output from the COCAR environment were very close to those defined by the industry.