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Preparação e caracterização de derivados de enzimas industriais em quitosana
(Universidade Federal de São Carlos, 2008-04-25) Adriano, Wellington Sabino; Giordano, Raquel de Lima Camargo; https://lattes.cnpq.br/1262160817438979
In this work, several strategies were tested to improve the covalent multipoint attachment of chymotrypsin, carboxypeptidase A and cellulase on chitosan. Hybrid gels with different internal structures were obtained using sodium alginate, gelatin or κ-carrageenan and by changing the polymer concentration, 2.5-5.0% (m/v) and the activating reactant, glutaraldehyde, glycidol or epichlorohydrin. The addition of microorganisms to the hybrid polymer followed by cellular lysis, the increase of immobilization reaction time and the effect of the reduction of the final derivative with sodium borohydride were also tested. The influence of these variables on immobilization yields, recovered activities, and stabilization factors at 55°C and 65°C, were assessed. Chymotrypsin derivatives half-lives increased from 34 min at 55°C (for pure chitosan 2.5% activated with glutaraldehyde at pH 7.0, 4°C) to 468 min at 65°C (for chitosan 2.5%-carrageenan 2.5%, with the addition of 5% of S.cerevisiae, activation with epichlorohydrin, immobilization for 72 h at pH 10.05, room temperature and reduction of the final derivative). This best derivative was 9900-fold more stable than the soluble enzyme. A maximum load of 40 mg chymotrypsin.g.gel-1 was reached. The number of aldehyde and oxirane groups generated in the support, and of lysine residues of the enzyme involved in the multipoint attachment, as well SEM images of the gel structures, explain the obtained results. Carboxypeptidase A derivatives was analyzed. The results showed that immobilization via epichlorohydrin presented 40% (8.8) more stable derivatives than glutaraldehyde ones (5.3). However, derivative prepared with epoxides groups presented 100% of immobilization yield with 57% of recovered activity being 20-fold more stable than free enzyme after 48h of immobilization process. Derivatives activated by glutaraldehyde, epichlorohydrin and with epoxides presented diffusion limitations with Deff of 5.41.10-12, 5.59.10-12 m2.s-1 and 5.10.10-12 m2.s-1, respectively. To cellulase, assays of immobilization and saccharification of sugarcane bagasse cane were tested. The derivative used in a sequence of three distinct batches, was prepared with chitosan-alginate activated with glutaraldehyde/glycidol being 20-fold more stable than free enzyme. The best enzyme derivative was about 38 fold more stable activated via glycidol. The performance of the system of saccharification was excellent, indicating that enzyme immobilization may be a good alternative to reduce costs of ethanol production from lignocellulosic materials.
Estudos ecotoxicológicos com ênfase na avaliação da toxicidade de surfactantes aniônicos aos cladóceros Daphnia similis, Ceriodaphnia dubia e Ceriodaphnia silvestrii
(Universidade Federal de São Carlos, 2008-04-25) Coelho, Katiuscia da Silva; Rocha, Odete; https://lattes.cnpq.br/7577441794992601; https://lattes.cnpq.br/4472303021113386
The main anionic surfactants world widely used are the sodium dodecyl benzene sulfonate (LAS) and sodium dodecyl sulfate (DSS), which are mainly used in the manufacturing of domestic and personal hygiene products. As a consequence of the great and increasing consumption of LAS and DSS there is an increasing wareness regarding the adverse effects of these compounds to the organisms and environment. The present study aimed to evaluate the acute and chronic toxicity of the compounds LAS and DSS to the cladocerans Daphnia similis, Ceriodaphnia dubia and Ceriodaphnia silvestrii. It was also evaluated the toxicity of the water and sediments of four reservoirs and one stream of São Paulo State Analyses of LAS concentrations in the water of these reservoirs were also performed by Liquid chromatography. Acute toxicity tests indicated a value of CE(I)50;48h for LAS of 14.17 mg L-1 to D. similis, 11.84 mg L-1 to C. dubia and 13.51 mg L-1 to C. silvestrii. Significant changes in the viability of the cladoceran offsprings were observed for C. dubia and C. silvestrii exposed to the LAS, with values of CENO equal to 1.0 mg L-1 to C. dubia and 2.5 mg L-1 to C. silvestrii. It was concluded that the maximum permissible concentration of 0.5 mg L-1 surfactants as established by the resolution CONAMA nº. 357/2005 (Brazilian Ministry of Environment) in order to protect aquatic communities is adequate, considering the sensitivity of the native species C. silvestrii. The results of the acute toxicity tests with DSS indicated a CE(I)50;48h value of 12.82; 4.37 and 5.42 mg L-1, for D. similis, C. dubia and C. silvestrii, respectively. A CENO value of 2.0 mg L-1 was obtained in the chronic toxicity tests for C. silvestrii. The surfactant LAS was detected in all the water samples collected in the Lobo (Broa), Lagoa Dourada and Fazzari reservoirs, but at concentrations lower than 5 mg L-1 (the method limit of detection). The toxicity tests with environmental samples revealed that there is no toxicity in the water of the Lobo and Lagoa Dourada sampled, however the water of Monjolinho Reservoir was toxic to D. similis and Fazzari stream was toxic to D. similis and C. dubia. Only the sediment of Monjolinho Reservoir was not toxic to cladocerans.
A avaliação institucional das escolas técnicas do Centro Estadual de Educação Tecnológica Paula Souza
(Universidade Federal de São Carlos, 2008-04-25) Silva, Marta Leandro da; Marques, Waldemar; https://lattes.cnpq.br/2975349587986383
Based on the qualitative research methodology in education, we discuss the institutional assessment on the policies of technological education reform, after LDB 9.394/96, focusing on the Institutional Evaluation System of Technological State Schools (SAI ETES) of Centro Paula Souza in the State of São Paulo (1997-2007). We aimed to analyze the conceptions and proposals of institutional assessment expressed by the legal and institutional discourse of Centro Paula Souza, as well as present the perceptions of educational agents (Directors, Coordinators, Teachers, Administrative technician) about the impact and impasses of such assessment policy in the Technological Schools in the context of democratic administration. It was evidenced that the institutional evaluation is presented in the legal speech as the quality support in the combination of the categories: evaluation, quality, autonomy and as an instrument of control-regulation of the public funding. In the Reform of the Public Apparatus the assessment is presented as a centralizing (and/or recentralizing) instrument of decentralization and exempting the state from responsibilities policies. In the perception of the educational subjects it is necessary to restructure the SAIETE, which emphasizes the results evaluation not considering the process evaluation. Assessment is considered an instrument to regulate public financing, expressed by the linkage among institutional assessment, individual performance assessment and salary bonus system. This assessment system does not consider the impacts of the technological education reform policies, as well as the diversity of pedagogical-organizational structures of agriculture and industrial technical schools, consolidated in different professional areas with different needs and political-pedagogical projects.
Formas plurais de governança no complexo agroindustrial citrícola: análise dos produtores de laranja da microrregião de Bebedouro/SP
(Universidade Federal de São Carlos, 2008-04-25) Mello, Fabiana Ortiz Tanoue de; Paulillo, Luiz Fernando de Oriani e; https://lattes.cnpq.br/9919942357089937
The citrus agroindustrial complex, that has the most of the citrus agroindustrial production in the state of São Paulo, constitutes a very interesting example of the interaction of different forms of governance. The very same producer manages his orange sales to the market agents in different ways: according to organizational theory this situation is called plural forms or contractual mix. On sales to buyers that will sell the fruit for in natura consumption the producer generally deals in terms of spot market. On the other hand, contracts are predominant in transactions with the juice-processing industry. The producer can also lease part of the unused capacity of an industry in order to process his own fruit and sell it straight to the market (quasi-integration) or integrate the sale of the in natura fruit becoming the owner of packing houses (hierarchy). This work aims to identify the reasons that lead orange planters to sell their product to different buyers employing different governances. We chose the Bebedouro microregion to carry out this work due to the fact that it is one of the most traditional in the state of São Paulo as well as in the context of the Brazilian agroindustrial citrus complex. The search for explanations for the occurrence of plural forms goes against, in principle, the assumption of predominance of the most efficient form in transaction costs, according to New Institutional Economic. Therefore, this is the theoretical foundation for this study, which has been complemented by authors of Economics of Organizations, who explain the coexistence of diverse arrangements within a same firm in franchising, agroindustrial systems and in distribution channels. One of the conclusions on the determinants of plural forms in the case of Brazilian citrus growing is linked to the fact that buyers from distinct channels of distribution (quantity, quality, fruit variety, location, etc) have specific needs, which generate restrictions that make the choice for multiple channels and forms of governance the only available for many producers. Nevertheless, the main conclusion is that the attributes of the transaction are the key factors to explain the occurrence of plural forms, i. e., it is the fact that transactions between producers and buyers are different in at least one attribute (specificity of assets, frequency or uncertainty) that explains the adoption of different forms of coordination.