Ciencias Exactas y Ciencias de la Salud
Permanent URI for this collectionhttps://hdl.handle.net/11285/551014
Pertenecen a esta colección Tesis y Trabajos de grado de los Doctorados correspondientes a las Escuelas de Ingeniería y Ciencias así como a Medicina y Ciencias de la Salud.
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- A comparative study on chemically and phytogenically synthesized TiO₂ nanoparticles and their role in modulating plant growth and metabolic dynamics(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2025-12-04) Bhatti, Atiya; Navarro López, Diego Eloyr; mtyahinojosa, emipsanchez; Sánchez Martínez, Araceli; Lozano Sánchez, Luis Marcelo; Mejía Méndez, Jorge L.; School of Engineering and Sciences; Campus Estado de México; López Mena, Edgar RenéThe present research provides a comprehensive investigation of the synthesis, characterization, and agricultural applications of titanium dioxide nanoparticles (TiO₂-NPs) developed via a conventional and eco-friendly (green synthesis method) route, focusing on their interactions with plant growth-promoting microorganisms (PGPMs) in order to boost the physiological and antioxidant performance of Capsicum annuum cultivars. The TiO₂-NPs synthesized through the molten salt method exhibited a nano-cuboid structure, a negative surface charge, and a moderate surface area. While green-synthesized TiO₂-NPs obtained from blueberry natural extracts using isopropanol (TiO₂-I.P) and methanol (TiO₂-M) exhibited mesoporous polyhedral anatase structures (E₉ ≈ 3.0 eV), hydrodynamic sizes of 130–150 nm, and stable ζ-potentials ranging from −33 to −50 mV. The extracts rich in flavonoid and phenolic compounds provided distinctive surface functionalities, improving the stability and bioactivity of the nanoparticles (NPs). In-vitro compatibility studies indicated that TiO₂-NPs facilitated microbial proliferation up to 150 µg/mL without exhibiting toxicity, thereby enhancing Bacillus thuringiensis (B.t) (1.56–2.92×10⁸ CFU/mL) and Trichoderma harzianum (Th) (2.50–3.90 × 10⁸ spores/mL), greenhouse experiments revealed significant enhancements in plants shoot and root growth, as well as increases in fresh weight (F.W) and dry weight (D.W) biomass and chlorophyll content. When TiO₂-NPs were utilized either independently or in combination with PGPMs B.t, Th. The synergistic treatments significantly improved antioxidant and enzymatic responses. Including peroxidase (69.90 UA/g F.W), β-1,3-glucanase (2.45 nkat/g FW), total phenolic content (29.50 GA/g FW), and chlorophyll accumulation (210.8 ± 11.4 mg/mg FW). In the context of green formulations were observed, TiO₂-I.P increased number of leaves and height of plant, whereas the root elongation not greater than control. Specifically with individual microorganism B.t, Th combined with at moderate concentration of TiO₂-I.P improved F.W and D.W. Peroxidase levels significantly increased when 50 µg/mL of TiO₂-M combined with microorganisms B.t+Th, While TiO₂-I.P stimulated a wider range of antioxidant responses, at 150 µg/mL of both formulation increased the total proteins. In case of total chlorophyll content increased at 150 µg/mL of TiO₂-I.P alone or combination of microorganism B.t+Th. The results emphasize biphasic behavior that is dependent on both formulation and dose, influenced by the surface chemistry of NPs and their compatibility with beneficial PGPMs. This work advances a practical framework for precision and sustainable agriculture through the integration of nanotechnology and microbial biotechnology. Where the surface chemistry of NPs and their biological compatibility can be tailored to ensure reliable and useful outcomes in agricultural fields.
- Discovery and comprehensive evaluation of new strategies for the postharvest biocontrol of anthracnose in avocado(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2025-06-10) Gallardo Camarena, Marco Vinicio; Licona Cassani, Cuauhtémoc; emimmayorquin; Reverchon, Frédérique; Méndez Bravo, Alfonso; Villalobos Escobedo, José Manuel; School of Engineering and Sciences; Campus Monterrey; Torres Acosta, Mario AntonioAnthracnose, caused mainly by Colletotrichum spp, is the leading postharvest disease affecting avocado (Persea americana), contributing to significant losses in global production. As concerns grow over the environmental impact and diminishing efficacy of synthetic fungicides, this study aimed to identify and evaluate microbial antagonists as sustainable biocontrol alternatives. Microorganisms were isolated from two primary sources: extreme environments in Cuatro Ciénegas, known for their oligotrophic and selective conditions; and various niches of the avocado ecosystem, including rhizosphere, carposphere, bark, and nectar. A total of 30 actinobacteria, 78 filamentous fungi, and other 13 bacterial isolates were screened in vitro against Colletotrichum spp., with promising candidates further evaluated through in vivo inhibition assays. Among the strains tested, Kosakonia cowanii VG1, isolated from the avocado carposphere, exhibited strong antifungal activity across assays. Genome analysis revealed biosynthetic gene clusters encoding siderophores and azole-containing RiPPs, which may underlie its inhibitory effects. The techno-economic evaluation showed a competitive production cost of $0.11 per dose, highlighting its scalability potential. Actinobacterial isolate Streptomyces nanshensis CC402A also demonstrated an effective in vitro and in vivo inhibition, with a low MIC and MFC of the crude extract. This isolate presents gene clusters for known antifungal metabolites, including valinomycin and HSAF-like compounds. This work supports the integration of prospecting in environments with strong ecological selective pressures, genomic mining, and economic modeling to discover and validate new microbial biocontrol agents.
- Development and in vivo evaluation of a probiotic-enriched functional beverage with Bacillus licheniformis for gut microbiota modulation in a high-fat diet model in C57BL/6 mice(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2025-01-01) Ramírez Olea, Hugo; Chavez-Santoscoy, Rocío Alejandra; Vázquez Lepe, Elisa Virginia; mtyahinojosa; Hernández Pérez, Jesús; Yolanda Arlette Santacruz Lopez; García Cayuela, Tomas; González Soltero, María del Rocío; Escuela de Ingeniería y Ciencias; Campus MonterreyObesity, type 2 diabetes, and other metabolic diseases are increasing across the globe. The necessity for public health to discover new interventions that can aid in fighting these conditions is crucial. Obesity, overweight, and diabetes are common conditions in Mexico. Over 70% of adults are overweight. Over a third are obese. Over 14 million people have diabetes. Understanding the link between these metabolic disorders with gut microbiota dysbiosis could therefore be critical to developing novel strategies for the prevention and treatment of these conditions. This PhD thesis intends to develop a functional drink using Bacillus licheniformis to modulate the gut microbiota and subsequently metabolism in general. In this thesis, a review of B. licheniformis was performed, enhancing its probiotic properties and mechanism of action concerning metabolic disorders such as obesity and diabetes. B. licheniformis was chosen due to its probiotic properties regarding microbiome modulation and its helpful effects on metabolic disorders. A native strain was isolated, sequenced, and optimized for use as a single-strain probiotic. Microencapsulation of the probiotic by spray drying using a maltodextrin-alginate-inulin matrix was statistically optimized and yielded microcapsules that have low moisture content (3.02%) and high yield (51.06%) and encapsulation efficiency (80.53%), solubility (90.52%), and stability at 4 °C, 25 °C, and 37 °C for at least six months, maintaining probiotic viability under simulated gastrointestinal conditions. Structural analyses (SEM, DLS, Zeta potential, FTIR, XRD, and DSC) showed interactions between the bacterium and the matrix, promoting an improvement in the amorphization, thermal stability, and release profile. The encapsulated probiotic has been added to a non-dairy functional beverage and shown to be viable through storage for over 6 months. Finally, it was evaluated in a high-fat diet Model using C57BL/6 mice. This functional beverage supplementation revealed a decrease in weight gain, prevention of hepatic steatosis, and systemic inflammation. At the same time, it improved glucose tolerance, biochemical profiles, gut microbiota diversity, and gene expressions compared to unsupplemented controls. By combining microbiology, materials science, and metabolic physiology, we present Bacillus licheniformis as a viable alternative platform for functional food products to aid in the control of obesity, diabetes, and other possible metabolic diseases through gut microbiota modulation.
- Optimization and sustained release of green lentil polyphenols through instant controlled pressure drop and encapsulation in PLGA nanoparticles(2024-12-03) Tienda Vázquez, Mario Adrián; Almanza Arjona, Yara C.; emimmayorquin; Cardador Martínez, Anabertha; Quintus Scheckhuber, Christian; Téllez Pérez, Carmen; School of Engineering and Sciences; Campus Monterrey; Lozano García, OmarThroughout history, legumes have been part of human consumption for their nutritional content and because is an easy crop to cultivate, it can grow in both cold and warm climates. One type of legumes are lentils, consumed worldwide. In Mexico, lentils are consumed by 70% of Mexican adults. Among the lentil varieties, green lentils stand out for having the highest polyphenol content, which makes them an excellent candidate for human consumption. However, the traditional way of cooking lentils requires prolonged times in boiling water. This causes a significant loss of the number of polyphenols present in lentils. Polyphenols have the ability to reduce the prevalence of suffering from chronic degenerative diseases, because they have antioxidants and anti-inflammatories properties. However, the chemical stability of polyphenols is compromised by different factors like the chemical structure, temperature, pH, isomerizations, enzymes, degradation, and oxidation, among others. This study subjected the green lentils to instant controlled pressure drop (DIC) and measured the polyphenol amount, flavonoids and antioxidant capacity 1,1 -diphenyl-2-picrylhydrazyl (DPPH) and Trolox equivalent antioxidant capacity (TEAC and DPPH), with 13 different treatments by varying pressure and time. The results showed that the polyphenols were the only parameter affected by DIC and the best conditions were less than 160 s and less than 0.1 MPa, and the best treatment was the DIC treatment 11, with 0.1 MPa for 135 s. Surprisingly, apparently new polyphenols appeared in the treated lentils due to the physical stress secondary to DIC, and in consequence the biosynthesis of polyphenols. After DIC, the best green lentil treatment was selected (DIC 11). The polyphenolic extract was obtained and nano encapsulated in poly lactic-co-glycolic acid (PLGA) using five different extract volumes (100, 250, 500, 750 and 1000 𝜇L). The nanoparticles were spherical in shape, with negative zeta potential charge (~ 20 mV), and all the syntheses produced particles, with average sizes ranging between 300 to 1100 nm. The polyphenol released was evaluated in PBS at pH 5.5 and 7.4. The release followed a triphasic controlled release, a lag phase of 24 h, a burst and diffusion phase from 24 h to 372 h, up to 15 days, and finally the saturation phase. The combination of the DIC technology as a pretreatment for green lentils and the nanoencapsulation in PLGA nanoparticles, improved the extraction and preserved the polyphenols profile of green lentils, on the other hand, nanoencapsulation protected the polyphenols and reached a controlled polyphenol release for up to 15 days.
- Exact and heuristic approaches for solving coverage and agricultural problems(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2024-12) Vicencio Medina, Salvador de Jesús; Ríos Solís, Yasmín Águeda; emimmayorquin; Cárdenas Barrón, Leopoldo Ediro; School of Engineering and Sciences; Cid García, NéstorIn this dissertation, two problems have been studied. The first problem, the maximal covering location problem with accessibility indicators and mobile units, belongs to the humanitarian logistic area. The second problem, the orthogonal site-specific management zone, belongs to the precision agriculture area. Both issues have been addressed through Operation Research techniques, which have a general purpose and can be used for various problems. The objective of the maximal covering location problem with accessibility indicators and mobile units is to allocate the COVID-19 tests to hospitals in Mexico to maximize the coverage, the number of opportunities, the service network, and other accessibility measures. To solve the maximal covering location problem with accessibility indicators and mobile units, a mathematical model that incorporates different accessibility measures and mobile units has been proposed. The mathematical model can solve small and medium instances in a short computational time. A matheursitic that combines an Estimation of Distribution Algorithm with a version parameterized of the proposed model has also been developed to solve medium and large instances. The computational results show that incorporating the mobile units with the accessibility measures considered has a significant improvement compared with the literature approaches. The orthogonal site-specific management zone problem aims to determine the minimum number of site-specific management zones that fulfill a homogeneity level measured through the relative variance. The zones must also be orthogonal since these shapes make it practical to delineate them for traditional agricultural machinery. An approximate and exact approach has been proposed to solve the orthogonal site-specific management zone problem.The approximate approach consists of a metaheuristic known as the Estimation of Distribution Algorithm. It uses a special decoder based on disjoint sets and a new reactive fitness function to provide high-quality solutions in short computational times. The results improve the solutions’ quality and computational times presented in the literature. Additionally, a new data set of instances has been proposed due to the results and times obtained with this approach. Using this new data set, the algorithm proposed continues to be fast and obtain quality solutions. Two mathematical programming formulations and one constraint programming formula-tion have been proposed for the exact approach. The mathematical programming formulations yield three cutting-plane algorithms. The formulations proposed obtain high-quality solutions for small and medium instances in short computational times. Besides, the formulations mentioned consider orthogonal management zones and the relative variance as constraints. To our knowledge, only heuristic methods have addressed this problem. Thus, the formulations presented in this work are the first in the literature to solve the orthogonal site-specific manage-ment zone problem. The computational results show that the formulations proposed obtain optimality for small and medium instances. Besides, these results make it possible to compare and validate the results obtained through the heuristics methods present in the literature.
- Canola protein – Extraction process by conventional and unconventional methods, functional properties, bioactivity, and uses in non-food applications(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2024-06-10) Chairez Jimenez, Cristina; Chuck Hernandez, Cristina Elizabeth; emimmayorquin; Espinosa Ramirez, Johanan del Pino; Santacruz Lopez, Yolanda Arlette; Rodríguez Sifuentes, Lucio; Escuela de Ingenieria y Ciencias; Campus Monterrey; Serna Saldivar, Sergio Roman OthonCanola protein (CP), which is extracted to canola meal, is a by-product of the canola oil extraction industry. This abundant and economical product has many functional and nutritional properties. CP has the potential to be used in the food industry because it is a protein with a well-balanced amino acid composition and promising functional properties that could be used in various food matrices. However, its utility is hindered by the presence of undesirable compounds such as glucosinolates, phytates, and phenols, which impart antinutritional properties and undesirable flavors and colors to CP. Because of this, it is important to look at different alternatives to take advantage of this by-product. This study addresses these challenges by exploring alternative protein extraction methods and evaluating their yield, functional, and nutritional properties. Subsequently, by nutritional properties, obtaining nutraceutical benefits, and functional properties, research their film-forming properties and how to improve these properties to develop a sustainable food packaging material. For the first step, the canola meal was subjected to different methods for extraction and purification. Alkaline extraction and ultrafiltration improved the yield (16.23%) and protein recovery (34.88%), and using ethanol as a pre-washing enhanced the functional and nutritional properties of canola protein. Subsequently, the impact of using Controlled Pressure Drop technology (DIC) as a pre-treatment for protein and phenolic extraction was evaluated where process time and pressure have a significant effect on phenolic extraction. To evaluate the nutraceutical properties, bioactive peptides derived from canola meal through enzymatic hydrolysis were investigated and evaluated for their antioxidant and antihypertensive properties. Bioactive peptides from canola meal and CP have antioxidant capacity and antihypertensive capacity near to 90%. Finally, CP has the potential to be used as a food packaging material, but it possesses some functional limitations that need improvement. Modified nanomaterials, plasticizers, and crosslinking agents were added to canola protein films. Incorporating graphite oxide resulted in a 665% reduction in oxygen permeability, a 70% decrease in water vapor permeability, a 400% increase in the contact angle compared to the control, and a 300% increase in tensile strength. These properties could make a sustainable alternative to producing food packaging material with appropriate functional properties.
- Study of secondary metabolites, microRNAs, and antidiabetic properties from the medicinal plant Murraya koenigii(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2023-05-31) Gutiérrez García, Claudia; GUTIERREZ GARCIA, CLAUDIA; 460587; Sharma, Ashutosh; emipsanchez; Paul, Sujay; Molina Aguilar, Christian; Díaz Muñoz, Mauricio; Paola Isabel, Angulo Bejarano; Escuela de Ingeniería y Ciencias; Campus MonterreyMurraya koenigii is a medicinal plant that grows in Asia and is distributed throughout India; however, it can also grow in Mexico. This plant is one of the few species that produce carbazole alkaloids which are therapeutic compounds with great commercial value. Traditionally, this plant is used to treat gastrointestinal disorders, inflammation, and diabetes, among other ailments. The plant's pharmacological properties are mainly attributed to its secondary metabolites, whose production depends mostly on its grown environmental conditions. Currently, only a few compounds have been identified; nevertheless, there is a lack of a secondary metabolites profile of the grown-in-Mexico M. koenigii. Additionally, the production of these compounds can be regulated post-transcriptionally by small non-coding RNA molecules called microRNAs (miRNAs). However, in the literature, there is no information available about its miRNA profile nor its implications in the synthesis of secondary metabolites. Additionally, diabetes mellitus is a metabolic disorder that affects more than 10 % of the world population and there is an urgent need for alternative treatments such as medicinal plants. Therefore, this project aimed to annotate the secondary metabolites profile of grown-in-Mexico M. koenigii and to reveal the microRNAs involved in their synthesis as well as to evaluate its in vivo antidiabetic potential. In the present study, 268 new compounds were tentatively identified from the methanolic extract of the leaves of grown-in-Mexico M. koenigii. Moreover, 142 conserved and 7 novel miRNAs were found, along with their target enzyme genes implicated in the terpenoid backbone and the flavonoid biosynthesis pathways. Also, this research project revealed that there was no significant decrease in blood glucose in M. koenigii-treated diabetic groups compared to the control group, but there was a decreasing tendency. Finally, miRNAs knowledge could improve the genetic engineering research to produce pharmaceutic and commercial secondary metabolites from M. koenigii, and further studies are suggested to continue investigating and validating its phytochemical content and its pharmacological properties.
- Biofortification of agri-food crops through sustainable bio- and nanofertilization practices as a strategy to jointly improve plant growth and increase the content of relevant phytochemicals and micronutrients(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2023) Guardiola Márquez, Carlos Esteban; Jacobo Velázquez, Daniel Alberto; emimmayorquin; López Mena, Edgar René; Navarro López, Diego Eloyr; Do Nascimento Simoes, Adriano; Morones Ramírez, José Rubén; Bioingenierías; Campus GuadalajaraModern agriculture faces important challenges to improve food security, it is evolving towards the use of novel biofortification technologies to improve agricultural productivity and fight nutrient deficiencies. Biofertilization and nanofertilization practices are increasingly used due to their efficiency, safety, and reduced environmental impact. Biofertilizers consist of formulations of plant growth promoting microorganisms that colonize the plants rhizosphere and promote plant growth by enhancing plant metabolism and improving nutrient uptake, while nanofertilizers are nanoscale nutrients with distinctive physicochemical properties that increase nutrient use efficiency. The general objective of this research work is to develop and evaluate biofertilizers based on native plant growth promoting microorganisms and zinc and iron nanofertilizers, to determine their potential to improve plant growth and biofortify agri-food crops with relevant phytochemicals and micronutrients. This work was divided in three specific objectives: (1) To isolate and characterize autochthonous microbial strains from important agri-food crops and nonagricultural plant species of northern Mexico with potential growth-promoting traits for the formulation of biofertilizers (Chapter 2). (2) To develop and evaluate zinc and iron bio-nanofertilizers formulated with plant growth-promoting rhizobacteria (PGPR) and microalgae preparations (Chapter 3). (3) To measure the impact of the combined application of biofertilizers of PGPR and zinc and iron nanofertilizers on plant growth and biofortification with glucosinolates and micronutrients in broccoli microgreens grown under seedbed conditions (Chapter 4). The main findings of the first approach included the isolation of PGPR of the Pantoea, Serratia, Pseudomonas and Rahnella genera, which showed potential PGP-traits and significantly increased the agronomic growth parameters of radish and broccoli seedlings. In the second approach zinc oxide (ZnO) and maghemite (γ-Fe2O3) nanoparticles were synthesized with the co-precipitation method and functionalized with Pseudomonas species and Spirulina platensis preparation. Results showed that ZnO- and γ-Fe2O3-nanoparticles treated with bacteria significantly improve the seedling vigor index (32.9–46.1%) of tomato and maize when applied at 75 ppm, while the same treatments applied at 250 ppm exerted better effects to improve the early plant development of radish and broccoli seedlings. The third approach revealed that the combined application of biofertilizers and zinc and iron nanofertilizers significantly improved plant growth (plant height (37–60%), leaf diameter (58–81%) and fresh weight (112–178%)), zinc (122–363%) and iron (55–162%) contents, and the concentrations of eight glucosinolates in broccoli microgreens. Biofertilizers and nanofertilizers are potential candidates to improve modern agri-food systems.
- Genetic and biochemical analysis of the microalgae desmodesmus abundans After 13 years under high-CO2 for flue gas mitigation in a two-stage continuous photobioreactor system(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2022-12-06) Mora Godínez, Shirley María; MORA GODINEZ, SHIRLEY MARIA; 827922; Pacheco Moscoa, Adriana; puemcuervo, emipsanchez; Rodríguez López, Carlos E.; Treviño Alvarado, Víctor; Rojas Jiméne, Keilor; Diaz de la Garza, Rocío I.; School of Engineering and Sciences; Campus Monterrey; Senés Guerrero, CarolinaMicroalgae present high potential for greenhouse gases mitigation and value-added biomass production. In this project, the main objective was to characterize genetic and biochemical changes of high CO2 (strain HCA, 50% v/v CO2/air) and low CO2 (strain LCA, atmospheric, 0.04% v/v CO2/air) acclimated strains of Desmodesmus abundans RSM to elucidate adaptation mechanisms to high CO2. Also, a two-stage continuous photobioreactor system for cement flue gas mitigation was designed and optimized; and microalgal biomass was characterized to optimize CO2 capture and propose high-value byproducts of the system. Additionally, strains potential for biological synthesis of silver nanoparticle was evaluated. These objectives were divided into five studies. In the first study, the genome of D. abundans RSM with an estimated size of 83.61 Mbp was generated. A total of 14 251 genes were predicted, and 58.68 % of these were annotated. Also, carbon fixation pathways were characterized in which ninety-six sequences codifying for twenty-two enzymes were found. Orthologous gene analysis showed 5 414 gene families conserved among D. abundans RSM, Scenedesmus sp. NREL 46B-D3 and species from the Selenastraceae family (M. neglectum and R. subcapitata). Genomic comparison between the strain maintained in our laboratory and the same strain deposited in UTEX Culture Collection of Algae resulted in 902 723 genetic variants which were mainly single nucleotide polymorphisms, and genomes presented 44.36 % of collinear genes. These results evidence genomic changes in microalgae as consequence of adaptation to laboratory conditions; but also conserved gene families between close species in the same taxonomic order (Sphaeropleales). In the second study, the genome of D. abundans after thirteen years of acclimation to high CO2 (strain HCA) was characterized and compared to the strain LCA. Also, both strains were grown under high CO2 acclimation strategy of six months and, growth and genetic variants were characterized. Assembled genome of strain HCA resulted in an estimated size of 81.20 Mbp, in which 10 535 genes were predicted. Evolution of the strain HCA was characterized by some differentially annotated GO terms to LCA, and in phylogenomic tree that located this strain in a different distance than strain LCA based on 514 single-copy orthologous gene families. Also, it was found only 15.65 % of collinearity between strain genomes and a low number of reads (35.70%) from strain HCA that mapped in LCA genome. Evaluation of high CO2 acclimation strategy for six months showed that strain LCA reached similar growth than strain HCA by the end of the experimental period. Microalgae adaptation to high CO2 involved higher accumulation of genetic variants (130 082) than under air (107 163), resulting in estimated mutation rates of 3.17x10-5 and 2.85x10-5 per base per generation, respectively. Strain HCA under air presented higher difficulties to adapt to this condition and accumulated 119 334 variants in air and 82 360 in CO2 with mutation rates of 3.56x10-5 and 2.25x10-5 per base per generation. High CO2 acclimation strategy of six months represents a simple and rapid way to generate higher CO2 tolerant strains. In the third study, strains LCA and HCA were grown in different N-concentrations under a continuous flow of high CO2. Growth, biomass composition and gene expression of N-transporters and biosynthesis of starch and triacylglycerol were characterized. Maximum cell concentration increased for strain HCA at higher N, but not for LCA. Also, only strain LCA showed an adaptation phase of 24 h for all conditions, and higher N intake rates were determined in HCA. Biomass productivities were not significant different among N concentrations and strains, ranging 0.097-0.134 g d.w. L-1 d-1. Similar biomass productivities evidence microalgae carbon allocation into different metabolites and therefore similar CO2 capture efficiencies. In both strains, under the lowest N (6 mg L-1) starch accumulated up to 12.7-14.52 % d.w., which in high N (50-250 mg L-1) was 5.1-7.1 % d.w. Contrary, protein decreased as N decreased in the medium from 43.3-54.8 % d.w to around 14 % d.w. While accumulation of neutral lipids occurred only in strain LCA for all N conditions. In conclusion, after thirteen years under low and high CO2 acclimation, strains present differential response to N concentration under high CO2. Growth and composition in strain LCA were affected by N and high CO2, while HCA only by N availability. This was also evident in gene regulation, where HCA presented a faster response to growth condition than LCA. A fourth study with strain HCA, evaluated the growth and nutrient utilization (CO2, NOx and SOx) of this strain under a model cement flue gas (MFG; 25% CO2, 700 ppm NO, and 100 ppm SO2) using a limited N and without S medium (BG11-0.2N-S) and complete medium (BG11) in an optimized two-stage continuous photobioreactor system (TSCB). Also, biomass composition (starch, protein, pigments and lipids) and productivities; as well as fatty acid profile were characterized. Microalga tolerated and used flue gas as nutrient source when using the TSCB system, and pH was successfully controlled through system stages by adding 150 mg L-1 d-1 of cement kiln dust (CKD). Biomass productivities was around 1.2 g L-1 d-1 for both culture medium. When using BG11-0.2N-S medium 26% lower protein than in complete BG11 were obtained, with productivities of 0.46 ± 0.05 and 0.63 ± 0.05 g L-1 d-1, respectively. Contrary, starch and lipid were higher in low N medium. Pigment concentrations were 1.3 to1.4-fold higher in complete medium. Fatty acid profile showed higher content of PUFA in free fatty acid fraction under limited N, and in di and mono- glycerides under repleted N condition. Biomass and metabolite productivities were improved by using the TSCB system compared to batch cultivation strategies. Target metabolite accumulation was induced by using different N concentrations, where limited N in the second stage allocate carbon into starch and lipids, while medium with extra N into protein and pigments. In the last study, the potential of D. abundans strain LCA and HCA was evaluated as a suitable platform for silver nanoparticle (AgNPs) synthesis. The effect of biological components, namely, cell pellet, supernatant, and both components, were compared to the culture collection strain Spirulina platensis at different pH values. All biological components of strain HCA at pH 11 showed potential for nanoparticle synthesis. AgNPs (14.9 ± 6.4 nm diameter) with the lowest charge (-32.7 ± 5.3 mV) were observed using the cell pellet and, preserving the supernatant, resulted in synthesis of AgNPs in all pH solutions. In contrast, no nanoparticles were observed with components of strain LCA, except for the cell pellet at pH 11 (127.8 ± 14.8 nm, -26.7 ± 2.4 mV). The reducing power in strain HCA might be attributed to functional groups from proteins, carbohydrates, and fatty acids; and, in the supernatant, to amino acids, monosaccharides, disaccharides, and polysaccharides. Finally, AgNPs of the three microalgae strains exhibited similar antimicrobial properties against E. coli in the agar diffusion test. It is suggested that the high CO2 atmosphere potentiates biological components in D. abundans strain HCA, which might benefit their use in nanotechnology and represent an exciting byproduct from CO2 mitigation systems.
- Anti-inflammatory phenolic compounds and capsaicinoids from chili pepper by-products (Capsicum chinense) recovered using assisted extraction techniques (ultrasonic and enzymatic)(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2022-11-22) Cortés Ferré, Héctor Emmanuel; Gutiérrez Uribe, Janet Alejandra; emipsanchez; Antunes Ricardo, Marilena; Ibarra Herrera, Celeste Concepción; Romero de la Vega, Gregorio; EIC Escuela de Ingeniería y Ciencias; Campus Monterrey; Guajardo Flores, DanielChili pepper industry generates wastes such as pulp, seeds or incomplete fruits that could be used to extract bioactive compounds with interesting health benefits like anti-inflammatory, anti-carcinogenic, anti-obesity, antioxidant among others. The aim of this research was to evaluate the use of assisted extraction techniques like ultrasound and enzymatic treatment to obtain chili pepper extracts from byproducts with anti-inflammatory and immune stimulant activities. Firstly, the evaluation of the Ultrasound Assisted Extraction (UAE) to recover capsaicinoids from pulp and seeds byproducts of Mora, Guajillo and Habanero chili peppers using methanol and ethanol as co-solvents applying two different extraction methods (Depletion and Equilibrium). The method that extracted the highest amount of capsaicinoids (159.36 mgCAP/g) was depletion with ethanol from Habanero pulp after 4 cycles, meanwhile the highest capsaicin concentrations were achieved in Habanero seeds after just one depletion cycle. Additionally, a cytoprotective effect was found in Mora byproducts extracts. Enzymatic assisted extraction (EAU) using a commercial cellulase complex in Habanero chili pepper seeds (CPS) at two concentrations (250 and 2500 UI/L) and three different temperatures (30, 45 and 60 ºC) during 150 minutes showed that the highest phenolic compounds content (337.96 mg GAE/L) was reached at 30 ºC, 2500 UI/L and 150 minutes. The maximum capsaicin [CAP] content (310.23 g/mL) was found at 45ºC with 250 UI/L for 150 minutes and the uppermost anti-inflammatory response was acquired when 60 ºC, 250 UI/L and 150 minutes reducing by 22.56% Nitric Oxide (NO) production. Finally, we discovered that among 15 phenolic compounds determined by UPLC-MS-QqQ in Habanero CPS extracts, vanillic acid (7.97-12.66 µg/g) was the most abundant. The extract obtained at 30 ºC and 120 minutes showed comparable effects than the detected for synthetic anti-inflammatory drugs indomethacin and dexamethasone. Capsaicin, salicylic, protocatechuic and trans-cinnamic acids as well as vanillin in CPS extracts were correlated with the anti-inflammatory effect.