Ciencias Exactas y Ciencias de la Salud
Permanent URI for this collectionhttps://hdl.handle.net/11285/551039
Pertenecen a esta colección Tesis y Trabajos de grado de las Maestrías correspondientes a las Escuelas de Ingeniería y Ciencias así como a Medicina y Ciencias de la Salud.
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- Optimization of synthesis conditions and physicochemical characterization of silver nanoparticles by cell lysate of lactobacillus rhamnosus(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2025-06-13) Flores Otero, Jesús Fernando; Aguilar Jiménez, Oscar Alejandro; emipsanchez; Santacruz López, Yolanda Arlette; Salas Villalobos, Ulises Andrés; School of Engineering and Sciences; Campus Monterrey; Ramos de la Peña, Ana MayelaNanomaterials have been present throughout history and, in 1951, Turkevich prepared metallic nanoparticles through a chemical mechanism for the first time. Many procedures for the synthesis of metallic nanomaterials exist, using both top-down and bottom-up approaches. However, as resources become scarcer and pollution increases, green methods have become more prominent, one such being biogenic synthesis as it takes advantage of biomolecules to replace chemical substances. In this work, silver nanoparticles were synthesized using Lactobacillus rhamnosus lysate to reduce silver nitrate, obtaining silver nanoparticles with a diameter close to 70 nm. The nanoparticles were characterized by Dynamic Light Scattering (DLS), X Ray Diffraction (XRD), UV-Vis Spectroscopy and Scanning Electron Microscopy (SEM). First, X-Ray Diffraction was used to determine the crystal structure and composition of AgNPs for comparison with previously reported studies. Henceforth, UV-Vis Spectroscopy showed an absorption peak at approximately 418 nm, which is within the UV absorption range for silver (400-460 nm). With these results, the nanoparticles were identified as AgNPs. Dynamic Light Scattering was used to optimize both the AgNPs size and size distribution (PDI) using a Factorial Design with three independent variables: reaction temperature, time and precursor (AgNO3) concentration. The optimal conditions for the formation of AgNPs were 60 °C, 60 minutes and 50 x 10-4 M AgNO3 concentration, obtaining an average particle size of 75.64 ± 3.04 nm and a PDI of 0.268 ± 0.014. In addition, zeta potential was measured to define the stability of AgNPs, with the previously mentioned optimized result having a Z-potential value of -36.07 ± 0.74. Scanning Electron Microscopy was used to confirm both the size and morphology of the AgNPs, observing particles of approximately the same sizes as the ones reported by DLS. Finally, the catalytic activity of AgNPs was tested with the degradation of methylene blue with NaBH4.
- Scale-up of a competitive and low-cost medium for prodigiosin production in a S. marcescens culture using biphasic systems as an integrated in-situ recovery process(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2020-06-15) Salas Villalobos, Ulises Andrés; AGUILAR JIMENEZ, OSCAR ALEJANDRO; 278440; Aguilar Jiménez, Oscar Alejandro; ilquio; Santacruz López, Yolanda Arlette; School of Engineering and Sciences; Campus Monterrey; Castillo Reyna, JosefinaProduct inhibition is an undesirable effect during fermentation that causes not only low yields but also a reduction in bioproduction feasibility of certain molecules. Prodigiosin is a secondary metabolite with an intense red produced by different strains of Serratia marcescens. Several in-vitro activities such as anticancer, antibacterial, immunosuppressive, anti-malaria and bio-colorant properties, make it particularly attractive to the pharmaceutical, food and textile industries. However, production of this natural alkaloid can be dramatically affected by media components and its antimicrobial activity causes end-product inhibition, additional to the complexity of typical production media making downstream processing complex and thus increasing the final cost of the purified product. In this study an optimization of a low-cost media using different sources and concentrations of carbon and nitrogen were performed. Extractive fermentation was evaluated as an integrated recovery strategy by coupling the upstream stage with different volumes of mineral oil as an extractive phase and we addressed the feasibility of scaling-up such extractive fermentation using batch and continuous processes modes. Peanut and defatted soybean meal in a 40 g/L - 5.25 g/L ratio, at 25 °C, achieved the best results, obtaining 584 mg/L of prodigiosin. The coupling of the medium with mineral oil at a 5% v/v presented a 1.12-fold in the prodigiosin content, which represents a change from 674 mg/L to 756 mg/L; and a 2-fold in cell growth. At scale-up tests, prodigiosin direct extraction produced in batch mode resulted in a prodigiosin concentration of 1282 mg/L. While continuous fermentation reached a concentration of 493 mg/L in steady state, which represents a 1.5-fold in the production rate compared to batch. A mathematical model, using Logistic and Luedeking-Piret equation was used to describe the microbial growth and product to correlate biomass and pigment production, obtaining correlation coefficients above 0.9747. The obtained results provide an opportunity to enhance prodigiosin production at the industrial level by alleviating end-product inhibition phenomenon using a two-phase system for in-situ primary recovery and putting in perspective with an economical approach. Also, this proposed strategy opens the possibility to transfer this experimental approach, for the recovery of several other hydrophobic molecules.
- Studies on the growth of magnetospirillum gryphiswaldense under several conditions and its influence on the production of magnetosomes(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2017-05-12) Rodríguez Ceja, Jesús Gilberto; Aguilar Jiménez, Oscar Alejandro; Parra Saldivar, Roberto; Rostro Alanís, Magdalena de Jesús; Santacruz López, Yolanda ArletteIn recent years, Magnetospirillum gryphiswaldense has called attention because it is a bacteria capable of producing magnetic nanoparticles (magnetosomes) that can be used in a variety of applications, such as directed therapies for drug delivery. The production of magnetosomes has not reach threshole concentration to ensure feasible for industrial applications. Thus, it is of high importance to increase the magnetosome production. This research evaluated the effect of stirring rate (100, 200, 400 and 600 rpm) and hydrodinamic conditions based on Reynolds number for the grwoth and production of M. gryphiswaldense. Overall, the better results were obtained at 200 rpm, with correspond to higher biomass and oxygen transfer coeficient (KLA). Optimal impeler stirring rate was selected to grow bacteria, followed by an anaerobic stage with feeding, to induce the production of magnetosomes. The best magnetosome yield obtained was 18.79 mg/mL*day in a fed-batch culture, 11.78 in continuous culture and 1.4 in batch culture. Their respective specific growth (μ) and generation time (min) were 0.083 and 8.31, 0.022 and 31.38, 0.02 and 34.65. Three different pellets were obtained and their magnetosome content was extracted to be analyzed in Z-sizer, resulting in an average size of 100 nm. Also aggregates of magnetosomes were found. The findings reported here could serve as a basis for the future scaling up of a biological factory for nanocarriers for multiple research and/or medical applications.