abstract
The work began with a bibliographical research on the microrreactors, its application in enzymatic processes, supports, types of enzyme immobilization and syntheses of esters in non-conventional medium catalyzed by lipases. The first laboratorial phase began obtaining the best conditions of immobilization of Candida antarctica lipase B (CALB) at bacterial cellulose (BC). The variables was enzyme concentration and the contact time between the solution and the BC. These optimum conditions were selected for immobilization by adsorption and by covalent bond. The conditions chosen were the concentration of 4mg/mL with an exposure time of 4 hours. In a second phase was tested the operational stability of the immobilizations in an aqueous medium, by enzymatic activity in several cycles of utilization (hydrolysis p-nitrophenol). In the stability test were distinguished two groups of immobilizations: the stored in the fridge (4ºC) and stored in the freezer (-18ºC) for both types of immobilization. Freezer immobilizations presented best operating resistance. It was not noticed a significant difference between the two types of immobilization, although the adsorption has been better in the first cycles and the covalent bond slightly higher than in the final cycles. In the final part, using the adsorption, it was attempted, without success, the synthesis of two esters, in particular the propyl gallate and eugenil benzoate, because they are two molecules with great potential for application in the pharmaceutical and food industries. However, it was possible to find a simple and rapid method for detection and analysis of esters by FTIR, using patterns. It was also found that the propyl gallate and gallic acid can be quickly detected by titration with sodium hydroxide (without extra indicator), through the different colours present, yellow and green respectively.
subject category
MESTRADO EM BIOTECNOLOGIA (2º CICLO)
authors
Bruno Miguel Marques Godinho
our authors
Bruno Miguel Marques Godinho
Researchersupervisors
Luísa Seuanes Serafim; Artur Jorge Faria Ferreira