http://repositorio.ufc.br/handle/riufc/429 2026-06-15T15:54:41Z 2026-06-15T15:54:41Z Barboza, José Anderson Lucas http://repositorio.ufc.br/handle/riufc/86643 2026-06-11T15:23:37Z 2028-01-01T00:00:00Z

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

2028-01-01T00:00:00Z Lopes, Marcos Vinícius Aquino http://repositorio.ufc.br/handle/riufc/86619 2026-06-06T22:44:14Z 2026-01-01T00:00:00Z

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

2026-01-01T00:00:00Z Nogueira, Karina Alexandre Barros http://repositorio.ufc.br/handle/riufc/86600 2026-06-03T18:11:29Z 2026-01-01T00:00:00Z

Título: Desenvolvimento de lipossomas e imunolipossomas de cloro alumínio ftalocianina contendo ácido oleico para potencial uso na Terapia Fotodinâmica em câncer Autor(es): Nogueira, Karina Alexandre Barros Abstract: Photodynamic therapy (PDT) is a promising cancer treatment modality, but its clinical success can be limited due to photosensitizer molecules, such as chloroaluminum phthalocyanine (AlClPc), being lipophilic and prone to aggregation in aqueous media, leading to a loss of efficacy. Consequently, the use of nanotechnologies, as well as chemical and/or physical absorption promoters, can decrease its toxicity and side effects. Squamous cell carcinoma (SCC) overexpresses the epidermal growth factor receptor (EGFR). Thus, the conjugation of the cetuximab antibody to liposomes containing AlClPc may favor cellular uptake. The use of physical methods capable of increasing skin penetration can also be applied. In breast cancer, the use of oleic acid incorporated into liposomes can be acted by regulating the neoplastic behavior of the cells. Thus, the present work aims to develop and physicochemically characterize liposomes and immunoliposomes containing oleic acid and AlClPc, to evaluate the use of photodynamic therapy in cutaneous SCC and breast carcinoma cells, and the use of physical methods for promoting skin penetration. To this end, a Quality by Design approach was employed, using a Box-Behnken design. Particle size, polydispersity index, and zeta potential were evaluated, and the encapsulation percentage was quantified by spectrofluorimetry. From the resulting formulation, composed of soy phosphatidylcholine (SPC), cholesterol (Col), oleic acid (AO), and DSPE-PEG (2000) in a ratio of 70:18:13.4:1.7, the conjugation of the cetuximab antibody was performed with a functionalization efficiency of 66.12%. In vitro studies were conducted on EGFR-positive cell lines (A431 and 4T1), resulting in better cytotoxicity for liposomes compared to the AlClPc solution. In in vitro skin penetration studies, a twice increase in AlClPc penetration was observed using microneedling in the viable epidermis. The mathematical modeling of the drug's diffusion process in the skin reinforces that the developed formulation exhibits retention behavior and slow diffusion between skin layers, which is ideal for topical application, with an R² = 0.94 and Dsc = 1.78x10-11 m²h-1. In conclusion, this work presents an innovative and multifaceted approach to improving PDT for cancer treatment. The liposomal system was successfully developed through factorial planning, as was the conjugation of the cetuximab antibody. The in vitro evaluation demonstrated the cytotoxic potential of photodynamic therapy, and the use of physical methods promoted greater skin penetration, showing its potential in the future of oncology. Tipo: Tese

2026-01-01T00:00:00Z Almeida, Cinthia Silva http://repositorio.ufc.br/handle/riufc/86142 2026-05-06T18:03:47Z 2026-01-01T00:00:00Z

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

2026-01-01T00:00:00Z