Rios, Nathalia SaraivaCosta, Isabela Oliveira2024-11-052024-11-052024-08-23COSTA, Isabela Oliveira. Produção de lipases imobilizadas em fibra de coco para a síntese de biodiesel via transesterificação. Orientador: Dra. Nathália Saraiva Rios. 2024. 131f. Dissertação (Mestrado em Engenharia Química) - Centro de Tecnologia, Universidade Federal do Rio Grande do Norte, Natal, 2024.https://repositorio.ufrn.br/handle/123456789/60512Biodiesel production through lipase-catalyzed transesterification of oils and fats is an alternative to traditional chemical catalysts. The enzymatic route provides conversion efficiency and minimizes side reactions, and can be carried out at temperatures considered mild. An efficient strategy to expand the advantages of using enzymes is their immobilization, which can be applied to improve enzyme stability, facilitating its recovery and reuse, and promoting protection against inhibitory effects. The immobilization support can be from several sources, including lignocellulosic waste, such as green coconut fiber. In addition to being less expensive, alternative supports are often evaluated as ecologically promising options in relation to commercial ones. Therefore, this work developed biocatalysts using green coconut fiber (CF) to support the immobilization of different lipases, aiming at application in the synthesis of biodiesel via transesterification of residual frying oil. Candida antarctica type B lipase (CALB), Pseudomonas fluorescens lipase (PFL), and Eversa lipase (EL) were the enzymes chosen for immobilization. Before this contact, the FC underwent a pretreatment with steam explosion to increase its surface area and facilitate the interaction to achieve immobilization. The immobilization yield (82.01 ± 2.02%, 87.62 ± 4.34% and 77.47 ± 1.88% for FC-PFL and FC-CALB in 24 h, and FC-EL in 48 h, respectively) and recovered activity of the biocatalysts (26.37 ± 2.25%, 49.84 ± 2.30% and 9.48 ± 0.11% for FCCALB, FC-PFL and FC-EL) showed that the individual immobilization of each lipase on coconut fiber was efficient. The obtained biocatalysts were subjected to postimmobilization chemical modifications with glutaraldehyde (GLU) to produce enzymesupport covalent bonds, followed by modification with polyethylenimine (PEI). The modifications were used to improve the thermal and operational resistance. Through the characterization of these three categories of biocatalysts, the results showed that the predominant interactions between enzyme-support are predominantly hydrophobic, the immobilization and coatings with GLU and PEI increased the thermostability at 60 ºC (FC-CALB-GLU-PEI: stability factor (SF) > 154.8; FC-PFL-GLU-PEI: SF > 58.6 and FC-EL-GLU-PEI > 172.6) of the lipases used and the presence of covalent bonding was observed by difference in the band pattern in the electrophoresis gel. For the application of these biocatalysts in the synthesis of biodiesel, the biocatalysts were used after determining the maximum enzyme load that can be immobilized, being 5 mg/g for the CALB biocatalysts, 10 mg/g for PFL and EL. The biocatalysts showed efficiency in reducing the acidity index similar to the soluble enzyme using the residual frying oil. The highest conversion was 13.67% of methyl esters when the reaction was carried out with 1 mmol residual frying oil: 10 mmol methanol and catalyzed by FC-EL-GLU-PEI, present at a concentration of 40% of the reaction medium, after 48 h of reaction. Under the same conditions, FC-CALB-GLUPEI and FC-PFL-GLU-PEI showed conversion of 0.73 and 7.23%. These results suggest the need for combined application of these immobilized enzymes or co-immobilized enzymes, aiming to achieve more competitive productivity.Acesso AbertoBiodieselLipasesImobilizaçãoFibra do coco verdeÓleo residualmasterThesisCNPQ::ENGENHARIAS::ENGENHARIA QUIMICA