DSpace Communidade:https://repositorio.ufba.br/handle/ri/26122026-04-17T03:38:42Z2026-04-17T03:38:42ZAplicação de técnicas não convencionais de extração para obtenção de bioativos em torta prensada de sementes de pracaxi [(Pentaclethra macroloba (Willd.) Kuntze)]Rodrigues, Willias da Luzhttps://repositorio.ufba.br/handle/ri/443482026-04-09T15:19:07Z2025-03-27T00:00:00ZTítulo: Aplicação de técnicas não convencionais de extração para obtenção de bioativos em torta prensada de sementes de pracaxi [(Pentaclethra macroloba (Willd.) Kuntze)]
Autor(es): Rodrigues, Willias da Luz
Primeiro Orientador: Silva, Silvana Mattedi e
Abstract: This doctoral research aimed to enhance the value of pracaxi press cake, a byproduct of oil extraction, by applying innovative and sustainable techniques aligned with the principles of green chemistry. The study focused on extracting bioactive compounds with antioxidant activity to enrich this industrial residue and strengthen the pracaxi production chain in the Amazon, thereby benefiting local communities. The methodology involved comprehensively characterizing the press cake and residual oil, including compositional, elemental, and mineral analyses. The microscopic structure of the press cake was examined using scanning electron microscopy (SEM), while Fourier-transform infrared spectroscopy (FTIR) was employed to identify functional groups. The physicochemical properties of pracaxi oil, such as density, viscosity, refractive index, and fatty acid composition, were investigated. Pressurized liquid extraction (PLE) techniques were applied using five solvents of different polarities (propane, ethyl acetate, ethanol, 75% aqueous ethanol solution, and water) with two distinct procedures: single-solvent extraction (SSE) and sequential two-solvent extraction (STSE). Mathematical modeling of pressurized liquid extraction kinetics was performed using models such as the two-line spline and the two-site desorption model. Additionally, enzyme-assisted extraction (EAE) was conducted using three commercial enzymatic complexes (Celluclast® 1.5L, Pectinex® Ultra SP-L, and Viscozyme® L), with water as the solvent. The obtained extracts were evaluated for their total phenolic and flavonoid content as well as their antioxidant activity (DPPH and FRAP assays). Furthermore, their antimicrobial activity against Staphylococcus aureus and Escherichia coli was investigated. The results demonstrated that pracaxi press cake is a rich source of bioactive compounds, with high crude protein (28.66%) and crude fiber (16.79%), while exhibiting low levels of potentially toxic elements. Elemental analysis indicated a predominance of carbon (50.50%) and nitrogen (4.18%), with molar ratios typical of lignocellulosic biomass. PLE proved to be effective in extracting phenolic compounds and flavonoids, with polar solvents such as ethanol-water (EtOH75) yielding the best results. The sequential two-solvent extraction (STSE) procedure, which used propane as a pretreatment, enhanced the efficiency of phenolic compound extraction. EAE, employing enzymes such as Pectinex® Ultra SP-L and Celluclast® 1.5L, improved the recovery of bioactive compounds, achieving high antioxidant activity—in some cases surpassing the results obtained with PLE. Mathematical modeling of extraction kinetics provided valuable insights for process optimization, enabling the identification of mass transfer mechanisms and optimal extraction times. The obtained extracts exhibited significant antioxidant activity, correlating with their total phenolic and flavonoid content, although no antimicrobial activity was observed under the tested conditions. This research highlights the potential of pracaxi press cake as a sustainable source of bioactive compounds, emphasizing the effectiveness of PLE and EAE techniques in their recovery. PLE offers flexibility in solvent and procedure selection, whereas EAE stands out for its use of an environmentally friendly solvent, water. These findings contribute to the full valorization of this agro-industrial residue, aligning with circular economy principles and promoting the sustainable development of the Amazon region
Editora / Evento / Instituição: Universidade Federal da Bahia
Tipo: Tese2025-03-27T00:00:00ZDeterminação do coeficiente de transferência de massa na remoção de propanona por absorçãoBarbosa, Isabel Barbosa ehttps://repositorio.ufba.br/handle/ri/442972026-03-27T16:12:32Z2024-07-12T00:00:00ZTítulo: Determinação do coeficiente de transferência de massa na remoção de propanona por absorção
Autor(es): Barbosa, Isabel Barbosa e
Primeiro Orientador: Góis, Luiz Mário Nelson de
Abstract: Air pollution from industries has been a frequently discussed topic today, generating the need to carry out studies on ways to reduce these impacts. Propanone is classified as a VOC (volatile organic compound) because it is a substance that in high concentrations generates risks to human health; and as it is present in industrial gas effluents, it is necessary to search for appropriate means to purify these gases. To carry out this type of treatment, studies focused on mass transfer through absorption were developed. The present work aims to determine the volumetric mass transfer coefficient of the liquid phase, KLa, in the removal of propanone present in the air by water using a stuffed absorption tower. The equipment used is 1,00 m high, 0,07 m in diameter and 0,79 m high filling glass rings. 33 experiments were carried out, at room temperature, at flow rates varying between 0,86 and 1,04 L min-1 of water and 0,4 to 1,2 L min-1 of air, in which, after contact between the liquid and gaseous streams, the Water samples are taken at an interval of 0 to 3,5 min to quantify the transferred propanone. The volumetric mass transfer coefficients on the liquid side obtained belonged to a range of 0,0044 to 0,0277 s-1, with a greater influence of the air flow on the KLa values in relation to the influence of the liquid flow. The equation developed in the dimensional analysis proved to be coherent, presenting an average error of 24%, and, when compared with some methods available in the literature, a better performance was observed, evidenced by the average error difference equivalent to more than 9%. Therefore, this study proved to be effective in the propanone transfer process, adding new data and empirical equations for the study of KLa.
Editora / Evento / Instituição: Universidade Federal da Bahia
Tipo: Dissertação2024-07-12T00:00:00ZOtimização do cultivo de chlorolobion braunii em associação de concentrado salino e água salobra: um bioprocesso para obtenção de biomassa e produção de biodieselMedeiros, Ravena Maria de Almeidahttps://repositorio.ufba.br/handle/ri/442882026-03-24T19:37:22Z2025-03-14T00:00:00ZTítulo: Otimização do cultivo de chlorolobion braunii em associação de concentrado salino e água salobra: um bioprocesso para obtenção de biomassa e produção de biodiesel
Autor(es): Medeiros, Ravena Maria de Almeida
Primeiro Orientador: Cardoso, Lucas Guimarães
Abstract: Effluents used as a culture medium for microalgae represent a strategy that combines
wastewater treatment—promoting nutrient removal—with the generation of high value-added
biomass. The ability of microalgae to accumulate lipids and carbohydrates in their biomass
makes them a promising source for biofuel production. The aim of this study was to optimize
the production and characterize the biomass of the microalga Chlorolobion braunii using a
combination of brackish water and saline concentrate, a condition not previously explored. In
addition, the potential of this biomass for biodiesel production was evaluated. The experiments
were carried out in Erlenmeyer-type bioreactors (1 L), and the best biomass production
condition was determined using a central composite rotational design with the following
factors: volume of saline concentrate in brackish water (0–100%) and urea concentration (0.00–
0.08 g/L). The optimized condition was defined as 36.6% saline concentrate, 63.4% brackish
water, and 0.02 g/L urea. The best treatment was the experiment with 50% brackish water and
50% saline concentrate, which produced 0.556 g/L of biomass with an average productivity of
0.014 g/L/day, and high levels of biomolecules such as 21.14% carbohydrates and 29.40%
lipids. It also achieved bioremediation of 86.25% of nitrates (NO₃⁻), 79.17% of phosphates
(PO₄³⁻), and a 23.18% reduction in salinity. The biomass showed high fatty acid content, with
24.94% C16:0 (palmitic acid) and 38.44% C18:1n9c (oleic acid), producing biodiesel that
meets the quality standards of the American Society for Testing and Materials (ASTM D6751)
and the Brazilian National Agency of Petroleum, Natural Gas and Biofuels (ANP). This study
optimized the biomass production of Chlorolobion braunii and demonstrated the feasibility of
using only a combination of brackish water and saline concentrate—without prior treatment
and without the addition of synthetic medium—resulting in high levels of biomolecules that
can serve as feedstock for the generation of high value-added bioproducts.
Editora / Evento / Instituição: Universidade Federal da Bahia
Tipo: Dissertação2025-03-14T00:00:00ZDesenvolvimento de nanocompósitos de quitosana e nanocelulose obtida por liquídos iônicos para mimetização ósseaVieira, Suellen Rochahttps://repositorio.ufba.br/handle/ri/442662026-03-19T16:37:36Z2026-12-19T00:00:00ZTítulo: Desenvolvimento de nanocompósitos de quitosana e nanocelulose obtida por liquídos iônicos para mimetização óssea
Autor(es): Vieira, Suellen Rocha
Primeiro Orientador: Assis, Denilson de Jesus
Abstract: The use of chitosan (CS) in the production of scaffolds, three-dimensional (3D), porous
structures that play an important role as support for the growth of new tissues, has emerged as
a promising alternative for biomedical applications, particularly in bone tissue regeneration.
However, the low mechanical strength of these materials suggests the incorporation of
nanomaterials, such as nanocellulose (NC), to provide structural reinforcement and broaden
their application potential. NC is biodegradable, biocompatible, renewable, and exhibits a high
surface area and mechanical strength, but its traditional production by acid hydrolysis (H₂SO₄
and HCl) leads to environmental impacts. In this context, ionic liquids (ILs) can be employed
as a sustainable alternative for producing these nanoparticles. This study aimed to map
technologies involving cellulose dissolution methods in ILs, identify major technological gaps,
and develop CS-based scaffolds reinforced with NC obtained from ILs to support bone tissue
regeneration. NC was produced from eucalyptus pulp using the ionic liquid 3-dimethylamino1-propylammonium hexanoate (DMAPA[Hex]) and characterized in terms of yield, zeta
potential, Fourier-transform infrared spectroscopy (FTIR), and transmission electron
microscopy (TEM). A central composite design (CCD) was used to optimize reaction time and
temperature. Patent analysis indicated that the technology is in an early stage of maturity, with
a predominance of applications in polymer chemistry and machinery, while uses in medical,
pharmaceutical, and micro/nanotechnology fields remain incipient, representing opportunities
for innovation. The optimal condition identified was 75 °C for 14.5 h, resulting in stable
cellulose nanofibrils (CNF) with well-defined morphology and a zeta potential of
approximately 7.0 mV, favorable for colloidal stability. The nanostructured scaffolds composed
of purified chitosan (CS-P) and CNF were produced in 3D format and characterized by XRD,
scanning electron microscopy (SEM), FTIR, and in vitro cell viability assays. The structures
exhibited interconnected porous networks with pores larger than 100 µm, providing a
voluminous matrix suitable for cell growth. CS-P improved the structural integrity of the
biomaterial, and cell viability tests demonstrated high biocompatibility. The integration of
technical performance, biocompatibility, and environmental responsibility positions the
CNF/CS-P scaffolds as promising candidates for regenerative medicine and advanced
biomaterials research.
Editora / Evento / Instituição: Universidade Federal da Bahia
Tipo: Tese2026-12-19T00:00:00Z