https://repositorio.ufba.br/handle/ri/20581 2026-05-17T06:05:46Z https://repositorio.ufba.br/handle/ri/43796 Título: Avaliação do uso de nano carreadores de ramnolipídeos associados ao fotossensibilizador azul de Taylor na terapia fotodinâmica antimicrobiana contra Staphylococcus aureus: estudo in vitro Autor(es): Jesus, Romário Santiago de Primeiro Orientador: Pinheiro, Antonio Luiz Barbosa Abstract: The increase in bacterial resistance to antibiotics has driven the search for alternative therapies, such as Antimicrobial Photodynamic Therapy (PDT). With the advancement of science, nanotechnology techniques are increasingly present, promoting the enhancement of existing techniques. This study evaluated, in vitro, the efficacy of PDT coupled with carrier nanotechnology against Staphylococcus aureus (ATCC 25923) in planktonic cultures, using the photosensitizer 1,9-dimethylmethylene blue (DMMB, λ ≈ 656 nm) and rhamnolipid nanocarriers (RL-NPs) produced by Pseudomonas aeruginosa. Seven experimental groups were established: Control (no treatment); LED (irradiation only, 20 J/cm²); DMMB (300 ng/mL); RL-NPs (300 ng/mL); RL-NPs/DMMB (300 ng/mL); PDT (DMMB + LED); and PDT+RL-NPs/DMMB (nanocarrier + LED). Photodynamic activation was performed with a prototype red LED (λ = 630 nm, power of 45.2 mW/cm²). Statistical analysis (one-way ANOVA with Tukey's post-hoc test) demonstrated that PDT promoted a significant reduction of ~2 logs (99.1%, p<0.0001) in bacterial viability. Notably, the group containing PDT+RL-NPs/DMMB nanotechnology showed a marked reduction of ~3 logs (99.9%, p<0.0001), significantly exceeding the standard PDT. The results indicate that the encapsulation of DMMB in rhamnolipid nanostructures enhances the antimicrobial efficacy of PDT. The characterizations performed on the nanocarrier elucidated in more detail the nature of the particles formed, including size, surface charge, and shape, which contributed to the enhanced effect, thus representing a promising strategy for the development of innovative clinical protocols against bacterial infections. Editora / Evento / Instituição: Universidade Federal da Bahia Tipo: Tese 2025-12-26T00:00:00Z https://repositorio.ufba.br/handle/ri/42749 Título: Potencialidades Cosmecêuticas e Biotecnológicas dos Extratos Vegetais de Hancornia speciosa Gomes: Fitoquímica, Fotoproteção e Metabolômica Baseada em Espectrometria de Massas e Impressão Digital Química Autor(es): Silva, Robson Almeida Primeiro Orientador: Vale, Ademir Evangelista do Abstract: The phytochemical study of plant species from the semi-arid and Recôncavo regions of Bahia has shown the presence of metabolites with relevant pharmacognostic and biotechnological properties. In a scenario of growing demand for sustainable solutions, the application of plant active ingredients in natural photoprotectors becomes a potential alternative. Hancornia speciosa Gomes has high antioxidant potential, although its use as a photoprotective agent remains incipient. This study investigated the chemical profile of extracts and fractions from the leaves and stem of the species using high-resolution mass spectrometry (UHPLC-HRMS), with subsequent analysis by molecular networks (Feature-based Molecular Networking - GNPS), and evaluated their antioxidant and photoprotective properties. A technological mapping was also conducted (via the PRISMA protocol) that showed the growth of innovations related to antioxidants and natural photoprotectors, although with limited Brazilian participation. The extracts were subjected to in vitro antioxidant tests (DPPH·, FRAP, total phenolic content and beta-carotene degradation), as well as determination of the sun protection factor (SPF) by the Mansur method. Additionally, a factorial design (33-1) was applied to optimize cosmeceutical formulations based on the extracts. The results indicated that the ethanolic extract of the stem (EETC) showed the best antioxidant performance (95.48±1.36% in DPPH·) and the highest reducing capacity in FRAP (45,008±858.30 µM FeSO₄/g). Metabolomic analysis revealed 56 putatively annotated compounds, distributed in 334 clusters and 3,481 nodes, highlighting glycosylated flavonoids, iridoids, pyrrolizidine alkaloids, carbohydrates and amino acids. A correlation was observed between the structure of glycosylated flavonoids and their antioxidant activity. In the antimicrobial screening, EETF inhibited Bacillus cereus (78.44±2.63%) and EETC was more effective against Candida auris (57.24±3.37%), with lower toxicity against Artemia salina. The optimized formulation with EETC obtained SPF higher than 44, demonstrating its high potential for cosmeceutical applications. Therefore, H. speciosa proves to be a promising source of bioactive metabolites, with prospects for the development of natural photoprotectors of high biotechnological value, reinforcing the importance of future studies, especially with the application of nanotechnologies. Editora / Evento / Instituição: Universidade Federal da Bahia Tipo: Dissertação 2025-07-14T00:00:00Z https://repositorio.ufba.br/handle/ri/42305 Título: Caracterização físico-química e microbiológica do rio Camarajipe e perspectivas biotecnológicas de biorremediação Autor(es): Costa, Geisa Louise Moura Primeiro Orientador: Matos, Josilene Borges Torres Lima Abstract: Introduction: Surface water contamination is a global issue largely driven by the eutrophication of rivers due to anthropogenic activities. A significant contribution to this scenario stems from the discharge of effluents and pharmaceutical and industrial ingredients, such as antimicrobials and recalcitrant compounds, which promote the emergence of multidrug-resistant (MDR) bacteria and infectious diseases. This reality constitutes a global public health concern; however, from a One Health perspective, it is possible to mitigate and remediate both chemical and biological contaminants. Objectives: To characterize the physicochemical and microbiological (quantitative and qualitative) parameters of water samples from the Camarajipe River in Salvador, Bahia, and to propose a sustainable solution for the bioremediation of recalcitrant compounds found in the river. Materials and Methods: To guide the research, a systematic review was conducted to investigate the antimicrobial resistance profile of bacteria in treated effluents from wastewater treatment plants in Latin America, following PRISMA guidelines and the PICO strategy. Over the course of seven sampling events, water samples were collected from four distinct sites along the Camarajipe River. These samples were analyzed for physicochemical parameters and processed for total and thermotolerant coliform counts. Furthermore, carbapenem-resistant Gram-negative bacilli (GNB) were isolated using selective culture media and identified via MALDI-TOF. Subsequently, bacterial susceptibility testing was performed on the isolates obtained. Additionally, experiments were conducted to develop a biological filter aimed at degrading recalcitrant compounds. Results: The systematic review revealed that the majority of wastewater treatment plants fail to eliminate MDR bacterial strains from treated effluents (19/20), as demonstrated through both physicochemical analyses and bacterial isolation. In the experimental study, physicochemical and microbiological analyses indicated that the Camarajipe River is eutrophic and functions as a reservoir for MDR GNB (43/47), which were found across all sampling sites. Among the isolates, strains of Pseudomonas spp. (31/47) and Klebsiella pneumoniae (11/47) were the most prevalent. As a bioremediation strategy, the constructed biological filter showed promising results in reducing Remazol Brilliant Blue, a recalcitrant compound associated with textile industry effluent contamination. Final Considerations: The Camarajipe River exhibits signs of eutrophication and acts as a vector for both chemical and biological contaminants, contributing to the spread of MDR GNB strains. As a potential tool to mitigate chemical pollution, the developed biological filter demonstrates promise; however, further testing is required to validate the prototype, including saturation and absorption capacity regeneration assays for the activated carbon. Editora / Evento / Instituição: Universidade Federal da Bahia Tipo: Dissertação 2025-03-12T00:00:00Z https://repositorio.ufba.br/handle/ri/41857 Título: Otimizações operacionais do cultivo de microalgas em água produzida da indústria do petróleo visando o seu tratamento e reuso em um processo de produção de bioativos Autor(es): Silva, Carine Souza da Primeiro Orientador: Chinalia, Fabio Alexandre Abstract: Produced water (PW) from the oil industry represents a significant environmental challenge due to its high salinity and complex chemical composition. Sustainable treatment of this effluent is essential to reduce environmental impacts and enable its reuse. Microalgae, such as Dunaliella salina, stand out as a biotechnological alternative for PW remediation, while also allowing the production of high-value biocompounds such as lipids and pigments. This study evaluated the effects of alternating electric current and different light spectra on the growth, biomass production, and accumulation of lipids and pigments in D. salina cultivated in PW and synthetic medium. Different electric current intensities (50, 750, and 990 µA) and frequencies (1, 50, and 100 Hz), as well as LED lighting with different wavelengths (red, blue, pink, and white) at a light intensity of 3,800 lux, were tested. The results showed that applying 50 µA at a frequency of 1 Hz, once a day for 30 minutes, in Conway medium with 8.5% salt salinity, promoted a 92% increase in specific growth rate. The highest biomass accumulation (70%) was observed in Conway with 3.5% salts, under electric stimulation of 50 µA at 1 Hz, once a day for 30 minutes. The intermittent treatment (5 minutes on and 5 minutes off), using 750 µA of alternating current at 1 Hz in Conway 3.5% salts, resulted in a 104% increase in lipid production. PW also showed positive effects under electrical stimulation. At 8.5% salinity, biomass production increased by 23% when applying 990 µA twice a day for 30 minutes. Meanwhile, an intensity of 50 µA applied once a day for 30 minutes led to a 66% lipid accumulation. Light stimulation also had positive impacts on D. salina: under red LED light, there was a 62% and 34% increase in specific growth rate and biomass production, respectively, and blue LED light stimulated lipid production by approximately 205%. These findings highlight the potential of combining electrical and light stimuli to optimize D. salina cultivation, contributing to sustainable bioprocesses and enhancing the feasibility of using PW as a culture medium in biotechnological applications. Editora / Evento / Instituição: Universidade Federal da Bahia Tipo: Tese 2025-04-04T00:00:00Z