https://repositorio.ufba.br/handle/ufba/556 2026-05-17T03:25:47Z https://repositorio.ufba.br/handle/ri/44286 Título: Bioprospecção de uma cianobactéria isolada no rio Joanes/BA para síntese de produtos visando aplicações biotecnológicas Autor(es): Pinheiro, Maria Teresa Araujo Primeiro Orientador: Sales, Emerson Andrade Abstract: Cyanobacteria represent the most diverse group of photosynthetic organisms on the planet and hold high potential for the discovery of novel bioactive compounds. Their pigments have well-established applications in food and nutraceutical products and also serve as valuable sources of proteins and other biomolecules. These characteristics broaden their potential use in sectors such as biofuels, food, animal feed, and, more recently, in the emerging field of phyconanotechnology. In this context, the aim of this study was to isolate a cyanobacterial strain from a river located in northeastern Brazil, analyze its potential for cyanotoxin production, and evaluate its application potential for obtaining bioproducts such as phycocyanin and carotenoids, as well as for the synthesis of carbon dots from laboratory-cultivated biomass and post-extraction residual biomass. The strain was isolated using a thermal method. Identification was carried out through a polyphasic approach, and cyanotoxin production potential was assessed by molecular and chemical methods (PCR and LC-MS²). Cultivation and growth kinetics were conducted under controlled temperature and light conditions to produce biomass, which was subsequently used for phycocyanin extraction, carotenoid identification, and carbon dot synthesis from residual biomass after bioactive extraction. The isolated and laboratory-cultivated strain was identified as Leptolyngbya boryana and was non-toxigenic. Phycocyanin extraction followed a protocol combining different solvents with freeze–thaw cycles. The most efficient extraction method employed calcium lactate at pH 9.47, yielding the highest phycocyanin content (153.24 mg/g of biomass). HPLC analysis revealed the presence of echinenone and chlorophyll a homologs in the biomass. Additionally, carbon dots were synthesized via a hydrothermal process from the cultivated species’ biomass (both before and after bioactive extraction), as well as from Chlorella vulgaris for comparison. Characterization of the carbon dot nanomaterials showed high fluorescence, photostability, and consistent performance in potential applications such as bioimaging, fluorescent sensors, and optoelectronic devices. Overall, the results indicate that the identified L. boryana strain possesses significant biotechnological potential, both for the production of phycocyanin and carotenoids and for the generation of nanomaterials of interest, highlighting the prospects for valorizing biomass into high-value products and commercial applications. Editora / Evento / Instituição: Universidade Federal da Bahia Tipo: Tese 2026-03-06T00:00:00Z https://repositorio.ufba.br/handle/ri/44099 Título: Estudo do estágio de maturidade da cultura de segurança de uma rede de revendas de GLP em Salvador - Bahia Autor(es): Mendes, Allen Greyson Gomes Primeiro Orientador: Gonçalves Filho, Anastácio Pinto Abstract: The Liquefied Petroleum Gas (LPG) distribution industry in Brazil faces significant challenges regarding operational safety, particularly within reseller networks. Despite the product’s importance for the national energy matrix and both residential and commercial supply, incidents related to inadequate handling, lack of standardized procedures, and the low maturity level of safety culture are still recurrent in part of the sector. In this context, the present study aimed to study the maturity stage of the safety culture in an LPG reseller network located in Salvador, Bahia. The research is grounded in well-established theoretical models that conceptualize safety culture as a set of values, practices, and collective behaviors that evolve through maturity stages. A mixed-methods approach was employed, combining quantitative and qualitative techniques. Data collection involved questionnaires covering six dimensions (leadership, commitment, involvement, information, communication, and organizational learning), along with a documentary evidence checklist. The sample consisted of 289 workers from 82 reseller companies. Results indicated an intermediate stage of safety culture maturity, between the reactive and bureaucratic stages, with significant variations across sociodemographic and organizational profiles. Positive correlations were identified between safety culture maturity and education level, age, and length of employment. Smaller resellers demonstrated higher levels of safety culture maturity. The findings suggest that advancing the maturity of safety culture within resellers depends on consolidating clear policies, implementing continuous training programs, and strengthening safety-oriented leadership. Furthermore, the development of monitoring tools and performance indicators is recommended to systematically track safety culture progress. This study contributes to the understanding of the current panorama of safety culture in the LPG distribution sector and provides practical insights for managers seeking to enhance operational reliability and reduce risks associated with reseller activities. Editora / Evento / Instituição: Universidade Federal da Bahia Tipo: Dissertação 0004-02-01T00:00:00Z https://repositorio.ufba.br/handle/ri/43582 Título: Uso de biomassa de microalgas e cianobactérias cultivadas em águas residuais de avicultura como potencial energético na produção de biodiesel e amônia como transportadora de hidrogênio Autor(es): Marques, Isadora Machado Primeiro Orientador: Sales, Emerson Andrade Abstract: Ammonia is used worldwide as a fertilizer, but its application as a hydrogen carrier has recently grown. It has the capacity to store hydrogen at 17.7% by weight (corresponding to 120 g/L), superior to methanol (12.5%). Certain microbial biomasses have the capacity to produce ammonia from gasification. The advantage is that these microorganisms can grow in wastewater, performing a dual role in the treatment of agro-industrial effluents and biomass generation. Thus, the objective of this work is to evaluate the cultivation of the microalga Desmodesmus sp. and the cyanobacterium Brasilonema sp. in poultry wastewater for the dual purpose of removing nutrients, nitrogen and phosphorus, as one of the industrial steps in effluent treatment and biomass reuse with potential generation of ammonia and biodiesel. The microorganisms were propagated in 3-liter borosilicate cylindrical photobioreactors. The growth of the microalga and cyanobacterium was monitored by chlorophyll (a) extraction using the solvent suspension method (SSM). Bacterial growth was monitored by the microdroplet plating technique. Wastewater characterization was performed to determine nitrogen by ion chromatography, phosphorus and chemical oxygen demand by spectrophotometer reading, and metals by ICP OES. The biomass was collected and characterized for carbon, nitrogen, oxygen, hydrogen, and sulfur composition through elemental analysis for simulation in Aspen Plus, in addition to lipid extraction and transesterification to evaluate biodiesel generation by fatty acid profile. Through modeling using the Aspen Plus program, the highest biomass generation was obtained from the microalga Desmodesmus sp. cultivated in poultry wastewater (PW) with a production of 1000 kg/h. The lowest production was obtained from the cyanobacterium Brasilonema sp. cultivated in BBM culture medium (CM), with 196.37 kg/h. The highest production of liquid ammonia was obtained from the biomass of the cyanobacterium Brasilonema sp. (PW) with 107.81 kg/h, followed by the microalga Desmodesmus sp. (CM) with 106.92 kg/h. Desmodesmus sp. (PW) showed a higher lipid content (23%) and protein content (42%) with greater CO2 biofixation (0.342 gCO2/L.d), reducing greenhouse gas emissions. Furthermore, it presented ideal proportions of the fatty acids palmitate (53.73% - C16:0) and oleate (8.75% - C18:1), improving the quality of biodiesel with a high cetane index and high oxidative stability. It was observed that for hydrogen generation, the best biomass was from the microalga Desmodesmus sp. cultivated in poultry wastewater, however, for ammonia production, the best species was Brasilonema sp. cultivated in wastewater, providing greater sustainability to the process. The discounted cash flow model indicated that the use of wastewater for ammonia and biodiesel generation reduces operational costs by approximately US$ 632,041.30 with a payback period of 4 years for return on investment. Thus, this study confirms and expands the evidence on the potential of microalgae and cyanobacteria as multifunctional biotechnological platforms, integrating waste treatment with the generation of clean and sustainable energy. Editora / Evento / Instituição: Universidade Federal da Bahia Tipo: Tese 2025-02-25T00:00:00Z https://repositorio.ufba.br/handle/ri/43529 Título: Avaliação das incertezas nas informações sobre as resistências à tração na flexão e compressão de argamassas cimentícias com lodo de ETA Autor(es): Souza, Thiago Francisco Primeiro Orientador: Kalid, Ricardo de Araújo Abstract: Research on the incorporation of water treatment plant sludge (WTS) into cementitious mortars plays an important role in environmental sustainability by enabling the reuse of solid waste and reducing improper disposal. This study investigated the incorporation of WTS, in both dried (uncalcined) and calcined forms, into Portland cement mortars, with emphasis on the measurement of flexural and compressive strengths, as well as on the evaluation of the uncertainties associated with these measurements. The sludge characterization included thermogravimetric analysis (TGA), X-ray diffraction (XRD), and the Modified Chapelle test. The XRD results indicated a high amorphous fraction in both dried and calcined samples, while the TGA defined 515 °C as the ideal calcination temperature. The consistency index showed that adding 10 % WTS significantly reduced workability (by about 40 %), whereas the mixture with 5 % WTS and superplasticizer maintained a consistency similar to that of the standard mortar. Regarding mechanical performance, the addition of 10 % dried WTS reduced flexural strength by approximately 64 % (2.7 MPa → 7.4 MPa control) and compressive strength by 42 % (14.4 MPa → 24.7 MPa control). The mixture with 10 % calcined WTS showed only a 4 % reduction, and the mixture with 5 % calcined WTS reached 30.9 MPa, about 25 % higher than the control, possibly due to the pozzolanic activity confirmed by the Pozzolanic Activity Index (PAI) and Modified Chapelle tests. The relative standard uncertainties for flexural and compressive strengths were below 5 %, consistent with laboratory measurement conditions. The analysis of the Kessel coefficients indicated that the applied load at the center of the specimens and the maximum failure load were the main contributors to the flexural and compressive strengths, respectively. The comparison of strength results, considering the expanded uncertainty, allowed the assessment of conformity with technical standards and the feasibility of using the mixtures in different applications. The study reinforces the importance of the metrological evaluation of uncertainties in mechanical tests, ensuring greater reliability and traceability of the experimental results of mortars incorporating WTS. Editora / Evento / Instituição: Universidade Federal da Bahia Tipo: Tese 0010-10-30T00:00:00Z