Ciencia e Ingeniería en Alimentos y Biotecnología

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Subject: search.filters.subject.ACTIVIDAD ANTIMICROBIANA

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    Análisis de la capacidad antimicrobiana de un péptido obtenido en un sistema de expresión Escherichia coli J53 frente a cepas de Staphylococcus spp.
    (Universidad Técnica de Ambato. Facultad de Ciencia e Ingeniería en Alimentos y Biotecnología. Carrera de Biotecnología, 2025-02) Llambo Charco, Darwin Marcelo; Garcés Moncayo, María Daniela
    Pathogenic microorganisms of the Staphylococcus spp. genius have represented one of the main causes of infections in nosocomial environments, immunosuppressed population, and patients with medical devices. The S. aureus strain has been particularly worrying due to its increasing resistance to antibiotics such as methicillin (MRSA) and certain beta-lactams such as cephalosporin and penicillin due to the presence of the mecA gene. Obtaining proteins from expression systems is a viable alternative for the development of new therapeutic avenues for infections caused by the Staphylococcus spp. genus. This research project was developed with the aim of analyzing the antimicrobial capacity of the peptide Alpha-1-Purothionine obtained in an E. coli J53 expression system against strains of S. aureus and coagulase-negative S. (CoNS). The process began with the cellular chemically competent of the host, induction with IPTG and the analysis of the expression by means of SDS PAGE, where a certain level of basal expression is evident. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were evaluated. Finally, it was determined that the peptide presented antimicrobial properties, inhibiting the growth and development of the S. aureus and CoNS strains through colorimetric verification using the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC), showing values of 8,5 micrograms per millimeters for S. aureus and 17,0 micrograms per millimeters for CoNS.
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    Uso de las propiedades antimicrobianas del quitosano contra patógenos alimentarios
    (Universidad Técnica de Ambato. Facultad de Ciencia e Ingeniería en Alimentos y Biotecnología. Carrera de Alimentos, 2025-02) Flores Barona, Joselyne Anabell; Sánchez Garnica, Manoella Alejandra
    This study focuses on the antimicrobial properties of chitosan to combat foodborne pathogens present in fresh cheeses, a significant public health problem due to foodborne illnesses. Pathogens such as Escherichia coli and Staphylococcus aureus are responsible for numerous foodborne infections, highlighting the need for effective alternatives to synthetic preservatives. The main objective of this study was to evaluate the efficacy of chitosan as an antimicrobial agent against these pathogens. The methodology included the determination of the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) by microdilution and disc diffusion techniques. Chitosan solutions were prepared, and their effects on E. coli and S. aureus strains isolated from fresh cheeses were evaluated. The results showed that chitosan had an MIC of 165 micrograms per millilitre for E. coli and 10 micrograms per millilitre for S. aureus, indicating an increased susceptibility of gram-positive bacteria. In addition, inhibition percentages of 62.5 percent for E. coli and 60 percent for S. aureus were observed. The most relevant findings suggest that chitosan is a promising natural preservative capable of inhibiting the growth of food pathogens, which could improve food safety and extend the shelf life of dairy products such as fresh cheeses without compromising their quality. Further studies are recommended to optimize its application in the food industry.
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    Evaluación de la actividad antimicrobiana in vitro de aceites esenciales frente a microorganismos patógenos y del deterioro de alimento
    (Universidad Técnica de Ambato. Facultad de Ciencia e Ingeniería en Alimentos y Biotecnología. Carrera de Biotecnología, 2025-02) Chango Chimborazo, Yajaira Estefania; Arancibia Soria, Mirari Yosune
    Essential oils (EOs) are volatile compounds, rich in secondary metabolites such as monoterpenes and sesquiterpenes, noted for their antimicrobial activity, attributed to their hydrophobicity and high concentration of active phenols (thymol, carvacrol, and eugenol). These compounds alter the integrity of microbial membranes, increasing their permeability and generating oxidative stress. The agar diffusion method is used to categorize antimicrobial activity into four levels (+++; fully inhibited, ++; partially inhibited, +; slightly inhibited, and -; no inhibition). However, this method presented limitations due to the volatility and hydrophobicity of EOs, which affected their uniform diffusion. The in vitro evaluation of 50 EOs against 12 microorganisms revealed greater efficacy against Gram-positive bacteria due to their more permeable cell wall. Although Gram-negative bacteria are more resistant due to their complex outer membrane. EOs such as thyme and oregano were able to inhibit them thanks to their bioactive compounds. In contrast, anaerobic Clostridium perfringens showed complete resistance, likely due to their spore-forming capacity and the reduced production of reactive oxygen species (ROS) in the absence of oxygen, which limits the antimicrobial action of EOs. In fungi, thyme and cinnamon showed significant activity, while against beneficial bacteria the action was minimal. Their efficacy depends on the active compounds, oil volatility, and experimental conditions. Finally, EOs represent a sustainable and natural alternative as antimicrobial agents, aligning with the Sustainable Development Goals (SDGs). Their application in the food and pharmaceutical industries can improve food safety and meet the demand for natural preservatives in consumer products.
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    Evaluación de las propiedades antimicrobianas del hongo cola de pavo (Trametes versicolor (L.) Lloyd) y su aplicación como conservante en queso fresco
    (Universidad Técnica de Ambato. Facultad de Ciencia e Ingeniería en Alimentos y Biotecnología. Carrera de Alimentos, 2025-02) Arteaga Teneda, Andrés Leonardo; Sánchez Garnica, Manoella Alejandra
    The excessive consumption of processed foods with high levels of chemical additives has generated concern owing to the potential adverse effects on human health in both the short and long term. In this context, fungi have been proposed as promising alternatives for the production of natural food additives because of their functional and beneficial properties, as well as their ability to replace synthetic additives. For this purpose, a methanolic extract of the turkey tail fungus (Trametes versicolor (L.) Lloyd) was developed using the maceration method, which achieved the extraction of secondary metabolites together with the solvent methanol. The antimicrobial properties of the extract were evaluated using the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) against Escherichia coli ATCC 11775 and Staphylococcus aureus ATCC 25923, using resazurin as an indicator, which allowed the observation of coloration changes. For food application, a fresh cheese was developed incorporating the fungus extract, and its shelf life was determined by counting colony forming units (CFU) per gram of Enterobacteriaceae for 5 days. In addition, the Arrhenius equation was used to predict its stability by comparing it with a traditional preservation method such as brine. The T. versicolor extract exhibited antimicrobial properties, as evidenced by the inhibition of the growth of the studied strains of E. coli and S. aureus, as confirmed by MIC and BMC assays. Likewise, the extract showed preservative effects in fresh cheese that were comparable to those obtained with brine, according to the results obtained through the prediction of shelf life based on the Arrhenius equation.
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    Eficiencia del almidón de chonta (Bactris gasipaes) como agente encapsulante sobre la actividad antimicrobiana de la doxiciclina
    (Universidad Técnica de Ambato. Facultad de Ciencia e Ingeniería en Alimentos y Biotecnología. Carrera de Biotecnología, 2025-02) Aponte Urrutia, Kerly Anais; López Hernández, Orestes Darío
    Doxycycline is an antibiotic of great interest in the health area, since it serves as a treatment for a variety of bacterial infections, but it has a drawback since it tends to degrade very easily at the time of its production, that is why new alternatives have been sought to preserve its bioactive components and protect it from contamination and even increase its bioavailability with the help of microencapsulation which is a technique that uses encapsulating materials such as natural polymers in order to generate greater effectiveness in encapsulation. For this, three suspensions were made with different proportions, using analysis techniques and verification of microencapsulation efficiency which were, performance analysis, statistical analysis, thermograms by means of differential scanning calorimetry (DSC) and antimicrobial evaluation, which was carried out by means of antibiograms of diffusion disks in Müller Hinton agar, to determine the inhibition of the microencapsulate against the E. coli bacteria. Through the different analyses carried out, it was obtained that the best performance and inhibition halos were given in the proportion 20:80, in addition to this, through the thermograms it was possible to observe the melting peaks where it was also represented that the best curve was that of the proportion 20:80. This is thanks to the fact that with a higher polymeric load, the percentage of microencapsulation efficiency increases. This could also be observed with the help of an-ANOVA analysis, which allowed the most significant performance to be seen through statistical graphs.
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    Determinación de la actividad antimicrobiana y antioxidante de los extractos de la planta sunfo (Clinopodium nubigenum) frente a cepas de Staphylococcus
    (Universidad Técnica de Ambato. Facultad de Ciencia e Ingeniería en Alimentos y Biotecnología. Carrera de Biotecnología, 2024-02) Chiriboga Cordones, Juan Fernando; De la Torres Olvera, Helena Maritza
    Foodsborne illnesses cause symptoms such as: diarrehea, vomiting and stomach pains; the treatment is the use of antibiotics such as: cephalosporins, penicillin and aminoglycosides. Due to the bad use, resistance has occurred to bacteria such as: E. coli, L. monocytogenes, S. aureus, among others. In the present investigation, the bacteria used was S. aureus and Coagulase Negative Staphylococcus (CoNS), obtained in cheeses from markets in the City of Ambato, where searched for an alternative to the use of antibiotics through antimicrobial tests and its relationship with the antioxidant activity. For this purpose, an extract of the Sunfo (C. nubigenum) was obtained, where its main components are polyphenols such as: flavonoids and phenolic acids. Through the Soxhlet method, secondary metabolites were obtained together with the solvent ethanol. The identification of the bacteria was realized on Salted Mannitol Agar, a yellow colour indicated the presence of S. aureus and a red colour indicated the presence of CoNS. For the antimicrobial test, the Minimum Inhibitory Concentration (MIC) and Bactericidal Concentration (MBC) were used together with the resazurin indicator, observing a change in coloration; for antioxidant activity, a colorimetric assay was realized with 2,2-diphenyl-1-picrylhydrazyl (DPPH). Finally, it was determined that the C. nubigenum extract presented antimicrobial properties, due to the inhibition of the S. aureus and CoNS species, verifying the colour change with the MIC and MBC test. Likewise, the evaluated extract presented antioxidant properties by reading absorbances between DPPH and the extract.
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    Obtención del péptido antimicrobiano aedesina por medio de un sistema de autoescisión mediado por inteina, utilizando un sistema de expresión en Escherichia coli BL21 (DE3)
    (Universidad Técnica de Ambato. Facultad de Ciencia e Ingeniería en Alimentos y Biotecnología. Carrera de Biotecnología, 2023-09) Mejía Bonilla, Dimitri Serge; García Solís, Mario Daniel
    Antibiotics have significantly improved people's lifestyle since their implementation. However, at present, the indiscriminate use of these drugs has generated a health crisis due to antimicrobial resistance. The current trend shows an increase in the number of resistant strains that cannot be treated with conventional antibiotics, which has led to the need to develop a new generation of antibiotics. One of the most promising alternatives is the application of antimicrobial peptides, among which aedesin stands out. The present research project focuses on the implementation of a purification strategy for aedesin. This strategy consists of an intein-mediated self-cleavable system, which possesses a prohibition condition that disables self-cleavage in the presence of high salt concentrations. A heterologous system of synthesis in E. coli BL21 was used for expression. In conclusion, synthesis in bacteria offers several advantages compared to other methods of obtaining peptides. Furthermore, the strategy used for the purification of aedesin has proven to be effective. However, there are still challenges to be overcome, such as peptide toxicity and basal expression. Despite these drawbacks, the successful expression and purification of aedesin position it as an interesting candidate for analysis in future clinical studies.
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    Determinación del efecto antioxidante y antimicrobiano de extractos de diferentes tipos de ortiga (Urtica dioica, Urtica urens, Urtica leptophylla, Urera baccifera) frente a cepas de Staphylococcus aureus, Escherichia coli, Listeria monocytogenes y Bacillus cereus
    (Universidad Técnica de Ambato. Facultad de Ciencia e Ingeniería en Alimentos y Biotecnología. Carrera de Biotecnología, 2023-03) Mariño Manzano, Kevin Daniel; Garcés Moncayo, María Daniela
    Medicinal plants have become a hope for the development of alternative medicines, for this reason, the WHO promotes the study of medicines based on plant sources, since they frequently generate few side effects, minimal toxicity and combat antimicrobial resistance. The Urticaceae family has a high index of bioactive molecules. This research focuses on evaluating the biological activity of hydroalcoholic (EtOH) and methanolic (MtOH) extracts from four nettle species. Initially, the extraction was carried out, which yielded variable yields, highlighting the MtOH of U. dioica corresponding to 2.487 percent as the best result. The antioxidant capacity was determined using the DPPH technique, all the extracts present considerable antioxidant activity, however, the MtOH of U. baccifera inhibited an equivalent to 435.80 micromoles of Trolox per liter. The quantification of total phenols was measured by the Folin Ciocalteu assay, which demonstrated that EtOHs exceed MtOHs. The hydroalcoholic extraction of U. dioica showed a higher amount of phenolic compounds (87,840 milligrams of gallic acid per gram). The antimicrobial activity was estimated by the microdilution method in 96-well plates based on resazurin, with which the MIC and MBC were determined. The extracts that inhibited at a lower concentration were: MtOH from U. baccifera and U. urens to E. coli and B.cereus, EtOH from U. urens and U. dioica to S. aureus and L. monocytogenes, respectively. In conclusion, the analyzed plant extracts have considerable biological activity.
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    Obtención de un péptido antimicrobiano autoescindible inducido por inteina utilizando un sistema de expresión en Escherichia coli
    (Universidad Técnica de Ambato. Facultad de Ciencia e Ingeniería en Alimentos y Biotecnología. Carrera de Biotecnología, 2023-03) Cordones Chimborazo, Kerly Lissette; García Solís, Mario Daniel
    Nowadays, there is a high prevalence of antibiotic resistance, which poses a danger to public health. In response to this global problem, arises the creation of antimicrobial peptides (PAMs), due to the wide antibacterial spectrum they exhibit. Based on this, cecropins sequences were used to design a peptide through ancestral reconstruction, from which an ancestral peptide called CRP_N0 was obtained. The current methods for the production of PAMs are chemical synthesis, plant cell production and direct extraction from natural sources. However, these methods have a high economic value and a low efficiency. Therefore, the peptide CRP_N0 was expressed by an intein-induced self-splitting system linked by its N-terminal end to six histidines. The six-histidine label was used to purify the fusion protein intein-CRP_N0 and the removal of intein from the peptide CRP_N0. The construction was inserted into the plasmid pET-11b and expressed in Escherichia coli BL21 pG-Tf1. To maximize the expression of the fission protein, different induction times were tested with IPTG and the optimal expression time was determined to be 4 hours. In addition, an excision test was also conducted in which different temperature and pH conditions were evaluated to induce self-excision of inteine, where it was determined that at 25 degrees Celsius and a basic pH (10) a high yield is obtained in the cutting of intein.
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    Caracterización y evaluación de la actividad antimicrobiana de una cubierta biodegradable de almidón de yuca enriquecida con aceite esencial de lavanda Lavandula angustifolia mill
    (Universidad Técnica de Ambato. Facultad de Ciencia e Ingeniería en Alimentos y Biotecnología. Carrera de Biotecnología, 2022-09) Guevara Morales, Christopher Josue; Tubón Usca, Irvin Ricardo
    Biofilms were made from cassava starch (5 percent weight on volume) and gelatin (5 percent weight on volume), plasticized with glycerol (3 percent weight on volume). The influence of the incorporation of different concentrations of essential oil of Lavender (Lavandula angustifolia mill) 1; 2.5; 5 and 10 percent, on the physical-chemical properties and antimicrobial activity of the biodegradable films produced. At a higher concentration of essential oil, the films become opaque and present a yellowish color, they are also heterogeneous and rough. The thickness and the Water Vapor Permeability (WVP) increase as the concentration of the essential oil increases. On the other hand, the solubility, swelling capacity and water vapor transfer rate (WVTR) show a tendency to decrease as the concentration of the essential oil increases. The humidity does not present a clear trend since it decreases up to a concentration of 2.5 percent and increases from the concentration of 5 percent A.E. The microbial inhibition halos are greater as the concentration of Lavender essential oil increases, indicating that the antimicrobial action is greater on S. aureus strains (ATCC 13150) and less on E. coli (ATCC 11229). Results were analyzed from one way ANOVA using GraphPad statistical software.