Ciencias Exactas y Ciencias de la Salud

Now showing 1 - 2 of 2

Synthesis of polyhydroxyalkanoates (PHAs) by Cupriavidus necator using nanoemulsified oils as a carbon source
(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2022-06-13) Martínez González, Sara; Sosa Hernández, Juan Eduardo; dnbsrp; Melchor Martínez, Elda Madai; Antonio Pérez, Aurora; Torres Huerta, Ana Laura; School of Engineering and Sciences; Campus Estado de México; Parra Saldívar, Roberto
Rising concern towards the global environmental crisis due to overuse of petroleum plastics and the rapid depletion of fossil fuels has created a renewed interest to biodegradable polymers. Polyhydroxyalkanoates (PHAs) are an example of biodegradable and biocompatible polymers, produced from renewable raw materials mainly by bacteria such as C. necator H16, a non-pathogenic strain that has genetic features to be only dedicated to PHAs and no concomitant products, also has the highest PHAs yields being 90% of cell dry weight. Nonetheless, manufacturing of biosynthesis of PHA is limited by its high cost compared with petroleum-derived plastics. Therefore, several research groups have focused on producing PHA with high productivity and yields to reduce the overall costs. One of these strategies consists in selecting inexpensive alternatives as carbon sources of the fermentation medium such as vegetable oils and supplement them after the adaptation stage of the bacterial culture. This approach has enhanced the intracellular accumulation of PHAs in bacterial cells and the thermomechanical properties of the polymer, but at the same time, the addition of insoluble oil to aqueous growth medium has led to an uneven dispersion of particles that makes this carbon source unavailable to the cells. Hence, this thesis project for a Master’s Program in Nanotechnology as a general objective is to design stable multiphase systems for the synthesis of biopolymers through the formulation of nanoemulsified oils as a strategy of medium optimization. In addition, this study aims to elucidate whether the use of nanoemulsified oils could help microorganisms to have a greater capacity for substrate consumption, due to the unique properties of nanoemulsions such as small droplet size, exceptional stability, transparent appearance and tunable rheology and consequently increase the overall productivity of PHAs and potentiate the thermomechanical properties of the polymer. In the present work, it is theoretically postulated that canola oil nanoemulsion contribution consists in the increase of the incorporation and consequently utilization rate of long-chain fatty acids (LCFA) excess presented on this nanoemulsion. Firstly, forcing Cupriavidus necator to switch to a fermentation pathway for the PHA biosynthesis, using as a fermentation-trigger, the LCFA excess and nutrient restriction (N, O, P, S, Mg). Secondly, shortening the lag time bacterium needs to liberate its biosurfactant in order to emulsify the canola oil, because an already nanoemulsion is being given to C. necator H16, then its lipases can be turned activated immediately by the nano-emulsified LCFA. Tirthly, canola oil nanoemulsion improvement comes with the LCFA incorporation-increase, thanks to the small nanoparticles which increase the total substrate area, it is justified, taking into consideration that bacteria lipases follow a no Michaelis-Menten kinetics, therefore lipase velocity rate is directly proportional to the total substrate area and do not for the substrate concentration. Regarding to the experimental approach, in the present work: formulation and characterization of emulsions were performed considering its further application as growth and PHA production media. The emulsifier that enabled kinetical stability was gum arabic even after autoclave sterilization process. Among the high energy methods used, the effect of the high-pressure disperser (Microfluidizer) on the particle size reduction was studied with respect to the rotor-stator type homogenizing disperser (Ultra-Turrax) achieving the highest (72.19 %) reduction at 4 % of oil and the lowest (38.68 %) one at 3% of oil content. In addition, the lowest particle size diameter of oil droplets was accomplished using the high-pressure disperser which was in the range of a nanoemulsion. With respect of the experimental strategy on biotechnological aspects, a first fed-batch bioreactor fermentation enabled the understanding of kinetic parameters to simulate using a Monod model, thus the next time the fructose concentration was increased 10-fold to and the experimental data adjusted to the predicted 30 g/L of biomass at 24 hours of the fermentation. Finally, the different levels of emulsification were assessed as growth media and microscopic characterization of gram stained C. necator H16 confirmed it, also the pellet area approach evaluating each stage of the biopolymer extraction gave a preliminary idea on a higher PHA production and also suggested suitable steps for the down streaming processing: biomass concentration, oil removal using ice-cold hexane, addition of a concentrated saline solution as emulsifier, and sodium hypochlorite to extract the biopolymer. This research sets a new and wide panorama on the applications of nanoemulsions in the field of biotechnology, in the future it is expected that this line of research includes the use of other microorganisms such as yeasts and fungi that utilize oil substrates. Also, the biosurfactant here explained in the proposed pathway that C. necator undergoes could be characterized.
Characterization and anti-inflammatory effects evaluation of chili oleoresin SNEDDS containing capsaicinoids
(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2021-06-03) Nava Ochoa, Ana Emilia; Guajardo Flores, Daniel; tolmquevedo; Gutiérrez Uribe, Janet Alejandra; School of Engineering and Sciences; Campus Monterrey; Antunes Ricardo, Marilena
Capsaicinoids are the compounds found in chili plants (Capsicum genus) that confer the pungency to the plant. These have been evaluated due to their anti- inflammatory and analgesic effects as they act directly by binding to Transient receptor potential vanilloid 1 (TRPV1), responsible for the perception and sensation of pain. Transdermal application of these compounds has its side effects as these compounds produce irritation in skin and burning sensation. Therefore, this work is focused on implementing these compounds into self-nanoemulsifying drug delivery systems (SNEDDS) for their potential of enhancing these compounds’ anti-inflammatory properties while reducing its side effects by changing its particle size and its properties. Oleoresins evaluated were obtained from Guajillo chili, Arbol chili and a synthesized oleoresin. Characterization and quantification of capsaicinoids on oleoresins were done by high performance liquid chromatography coupled with diode array detectors (HPLC- DAD) and they were reported as capsaicin equivalents. SNEDDS formulations stability was evaluated after 45 days and they were characterized by their particle size, zeta potential and polydispersity index (PDI) on a Zetasizer. SNEDDS entrapment efficiency (%) was also evaluated by HPLC-DAD. Lastly, in vitro tests were done to indicate anti- inflammatory activity. RAW 264.7 cells were used to determine nitric oxide (NO) inhibition, human dermal fibroblasts (HDFa) were used to evaluate cellular uptake and a fluorescent activity assay kit was used to evaluate COX-2 inhibition. As a result, the major capsaicinoids found were capsaicin and dihydrocapsaicin on Arbol oleoresin and four capsaicin analogues on the synthetic oleoresin. No capsaicinoids were found on Guajillo sample. Average entrapment efficiency was of 91.03%. Formulation stability was determined by PDI values which were lower than 0.500 on all samples and by zeta potential which showed an average of -18.98 mV, indicating formulation stability for both parameters. For cellular assays, RAW 264.7 cells showed no cytotoxicity from these compounds. Higher NO inhibition (%) was shown on SNEDDS formulation with synthetic oleoresin compared to normal oleoresins with an inhibition of 83.1 ± 1.99%. Synthetic oleoresin also showed the highest COX-2 inhibition with an activity of 79.19 ± 1.07%. Despite cellular uptake being higher on oleoresins, nanoemulsions showed a high cellular uptake of 21.18 ± 0.07% on synthetic SNEDDS formulations. This study showed the capability of oleoresins containing capsaicinoids incorporated into SNEDDS as anti- inflammatory agents. This type of formulations has the potential to be applied transdermally in order to be used on treatments for inflammation.

Ciencias Exactas y Ciencias de la Salud

Browse

Filters

Settings

Sort By

Results per page

Search Results