http://repositorio.ufc.br/handle/riufc/451 Wed, 10 Jun 2026 11:56:23 GMT 2026-06-10T11:56:23Z http://repositorio.ufc.br/handle/riufc/86643 Título: Imobilização da anidrase carbônica de Sulfurihydrogenibium azorense no suporte a base de sílica SBA-15 com poros expandidos para captura de CO 2 Autor(es): Barboza, José Anderson Lucas Abstract: The increase in carbon dioxide (CO 2 ) emissions, mainly from the use of fossil fuels, has intensified the search for sustainable technologies aimed at mitigating environmental impacts, such as global warming. In this context, biological carbon capture and storage processes have stood out due to their higher selectivity and operation under mild conditions, reducing energy consumption compared to conventional methods, such as chemical absorption. Therefore, this work aimed to evaluate the immobilization of carbonic anhydrase, derived from the heterologous expression of the ArticExpress (DE3) strain of the thermophilic microorganism Sulfurihydrogenibium azorense, on mesoporous silica SBA-15 (Santa Barbara Amorphous-15) with expanded pores, aiming to obtain a biocatalyst with higher stability and efficiency for CO 2 capture. For this purpose, the enzyme was expressed in Escherichia coli, extracted by cell lysis, and analyzed in terms of catalytic activity and zeta potential. The SBA-15 support with expanded pores was synthesized via a hydrothermal route and characterized by nitrogen adsorption/desorption isotherms, Fourier-transform infrared spectroscopy, and point of zero charge, resulting in the formation of a structure with ordered pores. Meanwhile, for the biocatalyst obtained by physical adsorption (SBA-AC), the effects of pH, ionic strength, protein load, and contact time during immobilization were measured. Protein yields were higher than 90% under almost all conditions, indicating strong affinity of the enzyme extract for the support, and the condition of 50 mg of protein per gram of support showed the best overall performance, with recovered activity above 80%. In addition, the support not only promoted enzyme immobilization but also provided partial purification of the extract, selectively retaining carbonic anhydrase over other proteins present. Furthermore, the storage stability of SBA-AC biocatalysts and those chemically modified with glutaraldehyde (SBA-AC-GA) was monitored over 90 days, showing not only maintenance but also an increase in catalytic activity during this period, with an approximate 25% increment in relative activity for both cases. Therefore, the results of this work demonstrate that the immobilization of carbonic anhydrase on SBA-15 with expanded pores is a promising strategy for CO 2 capture, presenting high catalytic performance and elevated storage stability. Tipo: Dissertação Sat, 01 Jan 2028 00:00:00 GMT http://repositorio.ufc.br/handle/riufc/86643 2028-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/86619 Título: Modelagem, simulação e otimização de um reator descontínuo heterogêneo para síntese enzimática de butanoato de etila catalisada por Novozym 435 Autor(es): Lopes, Marcos Vinícius Aquino Abstract: Ethyl butanoate is a relevant aroma compound in the chemical, pharmaceutical, food, and cosmetics industries. Its production via enzymatic esterification with heterogeneous biocatalysts, such as Novozym 435, is a promising alternative to improve yield and reduce the environmental impact of industrial processes. However, it still presents limitations due to the cost of biocatalysts and diffusional restrictions affecting the reaction rate. Thus, this study aimed to design a heterogeneous batch reactor through modeling, simulation, and optimization of ethyl butanoate synthesis using Novozym 435, focusing on process scale-up. Different mathematical models were proposed for the reactor, analyzing the relevance of internal and external diffusional limitations. The kinetic parameters and physical properties of the reaction system were obtained from the literature and empirical correlations. The reactor model with the best predictive capability, selected through an experimental validation test, was used in a sensitivity analysis to define process variables and performance and sustainability metrics. This served as the basis for the multi-objective optimization of the reactor operation, conducted for both batch and fed-batch configurations using butyric acid and ethanol, via Pareto front analysis. For scale-up, a constant power-to-volume ratio criterion was applied. Additionally, the costs of raw materials and the financial return of pilot-scale operation were estimated. The model considering internal diffusional limitations achieved a percentage error of 10.97% in estimating the reaction conversion profile. Simulations revealed that the initial substrate concentration and biocatalyst mass were the most relevant variables for achieving high productivity values. In the reactor optimization, the batch operation stood out, reaching an ester productivity of 1.13 g/h, a biocatalyst productivity of 44.41 kg p /kg c .h, and a product concentration of 1.95 M using 2.49 M butyric acid, 2.24 M ethanol, and 1.16% biocatalyst. During scale-up, the power-to- volume ratio remained at 173.70 W/m³, achieving an ester productivity of 9.26 kg/h in a volume of 82 L. The preliminary cost analysis reinforced the importance of maintaining biocatalyst stability over multiple operational cycles, focusing on process feasibility. Therefore, through simulation and optimization of the enzymatic synthesis of ethyl butanoate using Novozym 435, relevant data were obtained for designing a heterogeneous batch reactor, demonstrating higher production yields compared to the literature, as well as lower waste generation. Tipo: Dissertação Thu, 01 Jan 2026 00:00:00 GMT http://repositorio.ufc.br/handle/riufc/86619 2026-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/86142 Título: Síntese enzimática de biolubrificantes a partir de óleos vegetais e óleo fúsel, utilizando enzimas imobilizadas em compósito de lignina do bagaço de caju Autor(es): Almeida, Cinthia Silva Abstract: The environmental impacts of petroleum-based lubricants have sparked growing interest in the search for more sustainable alternatives. In this context, biolubricants emerge as a promising option, available from both synthetic and renewable sources. Among these, fatty acids extracted from vegetable oils stand out, conferring biodegradable properties and lower environmental toxicity to lubricants compared to mineral-based lubricants. Therefore, several strategies for biolubricant synthesis have been explored, including the use of biocatalysts. In this context, this study had two main objectives: i) to evaluate the production of fatty acids by enzymatic hydrolysis catalyzed by lipase from Rhizomucor miehei, targeting future applications; and ii) to evaluate the synthesis of biolubricants using free fatty acids (FFAs) obtained by chemical hydrolysis in combination with fusel oil, a waste product from the sugar and alcohol industry, as an alcoholic source. Initially, enzymatic hydrolysis studies of commercial soybean, canola, sunflower, and cottonseed oils were carried out by R. miehei lipase in its free form and immobilized on a magnetic support obtained from cashew apple bagasse lignin (Lig- Mag), for the production of free fatty acids. For this purpose, lignin was initially extracted from cashew apple bagasse, followed by the magnetization process and subsequent immobilization of the enzyme, evaluating two enzyme loads: 0.5 mg and 5 mg of protein per g of support, in which the obtained biocatalysts were named Lig- Mag_RML_0.5 and Lig-Mag_RML_5, respectively. In the hydrolysis tests, oil: water molar ratios of 1:1, 1:2, and 1:3 were evaluated at 50 °C, 150 rpm, for 24 h. As a result, it was observed that the highest hydrolysis percentages were obtained with cottonseed and canola oils, and the biocatalyst Lig-Mag_RML_5 presented the best performance, obtaining a hydrolysis percentage of 62.2 ± 1.8% for cottonseed oil and 53.4 ± 1.4% for canola oil. Subsequently, a study was carried out to evaluate the efficiency of the lipase B enzyme from Candida antarctica, in its free form and immobilized on the Lig-Mag support (Lig-Mag_CALB), in the esterification reaction using FFAs obtained by chemical hydrolysis and fusel oil as an alcohol mixture. The reactions occurred at acid: alcohol molar ratios of 1:1 and 1:3, at temperatures of 40 °C and 50 °C, for 48 h at 150 rpm. In the reactions conducted using Lig-Mag_CALB, the highest conversions were obtained with a 1:1 molar ratio and a temperature of 40 °C, reaching conversions of 72.4±1.3% and 73.9±0.6% using FFAs from cottonseed oil and canola oil, respectively. The biocatalyst showed satisfactory operational stability, reaching relative conversions of 66.8% with FFAs from cottonseed oil and 64.5% with FFAs from canola oil, after five evaluated cycles. Furthermore, when stored at 4 °C, it maintained 85% of its catalytic activity after 27 days. Both biolubricants obtained from canola 9 and cottonseed oils showed promising physicochemical properties, meeting the technical requirements for lubricant formulations. Therefore, enzymatic hydrolysis constitutes a viable alternative for obtaining free fatty acids, while transesterification presents itself as an efficient strategy for the synthesis of esters with lubricating properties. The use of residues such as fusel oil and cashew apple bagasse lignin contributes to the development of more sustainable processes, with the potential to generate biodegradable, non-toxic products and add value to industry by-products. Tipo: Dissertação Thu, 01 Jan 2026 00:00:00 GMT http://repositorio.ufc.br/handle/riufc/86142 2026-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/86139 Título: Estudo sobre a modificação do óleo vegetal de soja por interesterificação catalisada com a lipase Eversa Transform 2.0 para a produção de lipídios estruturados Autor(es): Silva, Laís Cândido da Abstract: This work presents a study on the use of the lipase enzyme Eversa Transform 2.0 in the interesterification of soybean vegetable oil, aiming to promote a rearrangement of fatty acid chains within the triacylglycerol molecule in order to obtain a structured lipid for application in the plant-based food industry. The composition of different vegetable oils with potential for blend formation was analysed. However, the initial synthesis trials were carried out exclusively with soybean oil in order to establish and optimize the reaction conditions. Thus, the effects of temperature and enzyme loading on the synthesis were investigated through the analysis of the composition of the vegetable oil and the synthesis products, as well as their structural conformation. The methodology adopted for these analyses was gas chromatography coupled with mass spectrometry. Structural changes were evaluated through the analysis of the sn-2 position of triacylglycerols, using the pancreatic lipase hydrolysis methodology, an enzyme present in pancreatin. A critical analysis of simplifying adaptations to this methodology was also performed in order to determine a more reproducible experimental approach. These adaptations included the removal of the thin-layer chromatography step, the exclusion of bile salts from the reaction system, and the use of hexane as an alternative solvent to diethyl ether. The results of the critical analysis of the pancreatic lipase hydrolysis methodology supported the maintenance of the thin-layer chromatography step for the characterization of the sn-2 position of triacylglycerols, as well as the use of bile salts in the reaction medium and diethyl ether as the extraction solvent, although the complexity of the method limits its application to a large experimental matrix. The synthesis results after 6 hours of reaction were more favourable under the conditions of 60 °C with 150 μL of enzyme, 70 °C with 300 μL of enzyme, and 80 °C with 150 μL of enzyme, which led to increases of up to 54% in saturated fatty acids at the sn-2 position compared to pure soybean oil. These findings contribute to the establishment of suitable reaction conditions for the enzymatic interesterification of soybean oil using the Eversa Transform 2.0 enzyme and to the validation of the structural analysis of triacylglycerols, providing a basis for the development of structured lipids with potential applications in plant-based industry. Tipo: Dissertação Thu, 01 Jan 2026 00:00:00 GMT http://repositorio.ufc.br/handle/riufc/86139 2026-01-01T00:00:00Z