Desenvolvimento de um biocatalisador a partir da co-imobilização da Dextrana-Sacarase e Dextranase em suporte Agarose-Epóxido

• Ano de defesa: 2018
• Autor(a) principal: Silva, Rhonyele Maciel da
• Orientador(a): Rodrigues, Sueli
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Palavras-chave em Português: Engenharia química; Biocatalisadores; Dextrana - Sacarase; Oligossacarídeos; Enzimas; Epoxy - Agarose; Co-immobilization; Dextransucrase; Oligosaccharides
• Link de acesso: http://www.repositorio.ufc.br/handle/riufc/30924

The current demand of green technology increases the interest in enzymatic process. Thus, enzymes immobilization is pointed as a key technology to improve the commercial viability of that biocatalyst, besides yield stability and reusability. Therefore, the industrial application of the enzyme dextransucrase is due to the production of dextran and prebiotics oligosaccharides. The complex structure of this enzyme turns its immobilization a tough task, because it has three subunits, besides a covalent dextran attached into one of its active sites. However, it is known that the hydrolysis of the endogenous dextran, by the enzyme dextranase, allows a greater interaction with the reactive groups of the supports. Thus, the objective of this study was to develop a biocatalyst in which the enzymes dextransucrase and dextranase are co-immobilized on epoxy-agarose support. This appears as an alternative to Eupergit C, a commercial support described as the most suitable for dextransucrase, but has been discontinued. Thus, the conditions of immobilization, pH and optimum temperature of enzymatic activity, as well as storage stability, operability and synthesis of oligosaccharides ere studied. The co-immobilization provides enzymatic activity in a wide range of pH and temperature for the biocatalysts (AGE-DS-DN0.5, AGE-DS-DN2.5 and AGE-DS-DN4.5). The biocatalyst AGE-DS-DN0.5 showed the highest activity recovered (59.54%), proving to be the most suitable for the subsequent tests. This was stable during storage at 4 °C, retaining activity above 70% for 60 days. In the production of oligosaccharides, AGE-DS-DN0.5 demonstrated the similar efficiency of the free enzyme with oligosaccharides up to 5 polymerization degree. In the evaluation of the operational stability AGE-DS-DN0.5 lost 60% of its activity in the first batch. After Fourier Transform Infrared (FTIR) spectroscopy, the enzyme desorption was observed during the batch. When comparing the AGE-DS-DN0.5 spectra with that of the Eupergit CM commercial support after reuse, it was seen that the enzyme interacts with other groups present in the commercial support, which are not present in the epoxy-agarose. Such groups would be responsible for the strong multipoint linkage generated between the enzyme and the Eupergit CM support, which prevented the leaching of the enzymes during the reuse cycles. Therefore, further studies are necessary to functionalize agarose with reactive groups, besides the epoxy, that allow a strong interaction between enzyme and support.