A. Téllez | Universidad Politecnica de Pachuca (original) (raw)

Papers by A. Téllez

Applied Biochemistry and Biotechnology, 2006

In this study, medium-chain-length polyhydroxyalkanoates (mcl-PHAs) were produced by Pseudomonas ... more In this study, medium-chain-length polyhydroxyalkanoates (mcl-PHAs) were produced by Pseudomonas aeruginosa using different carbon sources. Decanoic acid induced the highest (9.71% [±0.7]) mcl-PHAs accumulation in bacterial cells at 47 h. The cells preferred to accumulate and degrade the polyhydroxyoctanoate than polyhydroxydecanoate (PHD) during early stage and final stage of the growth, respectively. The production cost of mcl-PHAs can be reduced by using edible oils as the carbon source. The bacteria accumulated 6% (±0.7) of mcl-PHAs in the presence of olive oil. Besides, reused oil was another potential carbon source for the reduction of the production cost of mcl-PHAs. Overall, PHD was the major constituent in the accumulated mcl-PHAs. Index Entries: Edible oils; fatty acids; medium-chain-length polyhydroxyalkanoates; Pseudomonas aeruginosa.

Biotecnia, 2018

La bioactividad de los péptidos depende de la fuente y/o mezcla de proteínas empleadas. Phaseolus... more La bioactividad de los péptidos depende de la fuente y/o mezcla de proteínas empleadas. Phaseolus vulgaris L., es una opción para esto, ya que es una fuente importante de proteínas, pero su potencial no se ha estudiado a detalle. El objetivo del trabajo fue determinar las mejores condiciones de hidrólisis enzimática del concentrado proteico de dos variedades de frijol común (Negro Primavera-28 [CPPv-28] y Flor de durazno [CPPv-Fd]) para obtener péptidos bioactivos. En primera instancia, se establecieron las condiciones de hidrólisis del CPPv-28 y CPPv-Fd, los factores evaluados fueron: pH y actividad proteolítica del extracto de Pleurotus ostreatus (EEPo); y las variables de respuesta fueron: contenido de péptidos liberados y actividad antioxidante. A partir de esto y por medio de la metodología de superficie de respuestas, se llevó a cabo el proceso de optimización. Se encontró que el EEPo liberó péptidos con actividad antioxidante, asimismo, las mejores condiciones de hidrólisis s...

Revista Internacional de Contaminacion Ambiental

With the purpose of increasing the amount of sugars that benefit the yield of ethanol in fermenta... more With the purpose of increasing the amount of sugars that benefit the yield of ethanol in fermentation, it was performed hydrolysis of Beta vulgaris L. with H2SO4. The following parameters were used to evaluate the degree of hydrolysis of substrate: stirring, acid concentration, mass, and temperature. The mass was tested in the range of 5 to 40 g and stirring from 100 to 250 rpm. The temperature and reaction time were evaluated in the range of 30 to 90 °C and 2 to 6 h, respectively. The tested particle size was 0.5 mm and a reaction volume of 50 mL was used for all cases. The rate of 150 rpm had a better effect over hydrolysis. By comparison of means it was determined that concentrations higher than 0.5 N of H2SO4 showed no significant effect (p<0.05) on the release of total sugars. The highest yield of hydrolysis was obtained with 10 g of substrate in the reaction medium. The temperature of 90 °C provided the highest hydrolysis and at 50 °C the amount of total sugars was 3 g/L lo...

Forest Systems, 2010

Las lacasas (EC 1.10.3.2) son enzimas del grupo oxidasas azules que contienen átomos de cobre en ... more Las lacasas (EC 1.10.3.2) son enzimas del grupo oxidasas azules que contienen átomos de cobre en su es-tructura, tienen baja especificidad por sustrato, reducen el oxígeno molecular a agua y pueden oxidar diferentes compuestos fenólicos y no fenólicos (González et al., 2005). Las lacasas secretadas por los hongos participan en varios procesos celulares, incluyendo deslignificación, esporulación, producción de pigmentos, formación del cuerpo fructífero y en mecanismos de patoge

Journal of Basic Microbiology, 2004

Fungal Genetics and Biology, 2004

Nine phenolic compounds (p-coumaric acid, ferulic acid, guaiacol, syringol, p-methoxyphenol, pyro... more Nine phenolic compounds (p-coumaric acid, ferulic acid, guaiacol, syringol, p-methoxyphenol, pyrocatechol, phloroglucinol, 3,5dihydroxybenzoic acid, and syringaldazine) were tested for their ability to increase laccase production in the ligninolytic basidiomycete Trametes sp. I-62. All these compounds resulted in increases in laccase activity, with the highest levels being detected in the presence of p-coumaric acid (273-fold) and guaiacol (73-fold). The three laccase isozyme genes in this fungus lcc1, lcc2, and lcc3 are differentially expressed in the presence of some of these aromatics with total lcc transcript levels differing markedly depending on the aromatic compound tested. Guaiacol (the best inducer of lcc gene transcription) and p-coumaric acid selectively induced expression of lcc1 and lcc2; ferulic acid induced lcc3 expression, while 3,5-dihydroxybenzoic acid had no marked effect on laccase gene transcription. The results demonstrate that close-related aromatic compounds appear to have different effects on both laccase activity levels and lcc gene expression in this basidiomycete.

Enzyme and Microbial Technology, 2006

Bioresources

Straw is an agricultural byproduct that can be utilized to obtain bioethanol without affecting an... more Straw is an agricultural byproduct that can be utilized to obtain bioethanol without affecting animal or human sustinence. This process involves recovering the sugars and reducing the lignin content present through the use of ligninolytic fungi such as the basidiomycete Trametes sp. 44. Fermentation was carried out using particle sizes 4 (4.76 mm, No. 4 sieve) and 8 (2.30 mm, No. 8 sieve), and two velocities of airflow (100 and 200 mL/min). Study results showed that particle size affected the production of hydrolytic enzymes, as particle size 8 favored the expression of cellulases and hemicellulases. In addition, both aeration and particle size affected the expression of ligninolytic enzymes, as it was observed that with particle size 8 and airflow of 200 mL/min, the study detected 63 AU/mL of LiP and 11 AU/mL of MnP. In the case of laccase, the enzymatic activity detected reached 220 AU/mL using particle size 8 and an airflow velocity of 200 mL/min. Statistical analysis indicated t...

Electronic Journal of Biotechnology, 2006

Revista de la Sociedad Química de Mexico, 2017

Traditional methods used for concentration of whey pro- teins have various levels of performance ... more Traditional methods used for concentration of whey pro- teins have various levels of performance and effects on the nutritional properties and biological activities of the products. In this study, we showed that the greatest protein content was obtained using ultrafil- tration and salt treatment methods. The effective concentration was approximately 40-53% (w/w) protein. Using electrophoresis and solu- bility tests, we also found that these methods offer the fundamental advantage of maintaining certain proteins in their native states. The products maintained key ABTS•+ radical scavenging activity; how- ever, the antimicrobial activity was adversely affected by these sepa- ration methods.

Foods

Mesquite (Prosopis laevigata) is a legume tree widely distributed in Aridoamerica. The mature fru... more Mesquite (Prosopis laevigata) is a legume tree widely distributed in Aridoamerica. The mature fruit of this legume is a pod, which is currently underutilized and has high nutritional potential. In the present work, mesquite seed flour is described in terms of its nutritional value, as well as the effect of extrusion cooking on its bioactive components. Mesquite seed flour is rich in fiber (7.73 g/100 g) and protein (36.51 g/100 g), with valine as the only limiting amino acid. Total phenolic compound contents in raw and extruded seed flour were 6.68 and 6.46 mg of gallic acid equivalents/g (mg GAE/g), respectively. 2-2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity values in raw and extruded seed flour were 9.11 and 9.32 mg of ascorbic acid equivalent/g (mg AAE/g), respectively. The absorbance at 290 nm, as an indicator of generation of Maillard reaction product (MRP), was the same for raw and extruded samples. Apigenin was the only flavonoid found in mesquite seed flou...

Physics Procedia, 2010

Oncology hyperthermia refers to an artificial elevation of temperature in biological tissue to re... more Oncology hyperthermia refers to an artificial elevation of temperature in biological tissue to remove tumor cells. This temperature increase is reached by applying ultrasound or electromagnetic waves. Working with biological tissues implies a high effort; furthermore, biological material changes its properties with time. Also, it is necessary a knowledge of the handling of biological material and a specialized infrastructure. For these reasons, for some years our research laboratory has dedicated part of its researches to develop mimicking materials to emulate muscle and other tissue ultrasonic properties. A blood phantom was developed in our laboratory for its use in the transit time flow measurement (blood flow). The properties of interest for the muscle and for the blood phantoms are ultrasonic attenuation and ultrasound velocity. This work refers to the phantom preparation and their ultrasonic properties measurement. These phantoms emulate the mentioned ultrasonic characteristics. In the case of muscle, there are two types of phantoms: solid phantom with graphite and phantom with scatterers. The procedure of preparation of the phantoms is described. They have a different composition to that published for Doppler blood phantoms. Some ultrasonic properties of muscle and of blood have been already published and they are referred to one temperature. An originality of the results reported in this paper is that the behavior of the ultrasonic properties is presented at different temperatures: ranging from 22°C to 470°C. This range includes the temperatures used in our experimental work in hyperthermia treatment.

Fermentation

The growing demand for natural products benefits the development of bioprocesses to obtain value-... more The growing demand for natural products benefits the development of bioprocesses to obtain value-added compounds using residues such as sweet whey, which is rich in lactose. The yeast Kluyveromyces marxianus can ferment sweet whey to obtain 2-phenylethanol (2-PhEtOH), which is a superior alcohol with a rose aroma. Such fermentation only requires the addition of L-phenylalanine (precursor) and (NH4)2SO4 (salt). Therefore, it was sought to improve the fermentation conditions to produce 2-PhEtOH, which, in turn, would achieve the maximum decrease in the Chemical Oxygen Demand (COD) of the fermentation medium. With the use of the Response Surface Methodology and the application of a Central Composite Design for optimization, two parameters were evaluated as a function of time: salt concentration and precursor. The experimental data were adjusted to a second order polynomial, identifying that the precursor concentration presents a statistically significant effect. The best conditions wer...

Con el proposito de incrementar la cantidad de azucares que beneficie el rendimiento de etanol en... more Con el proposito de incrementar la cantidad de azucares que beneficie el rendimiento de etanol en la fermentacion, se realizo la hidrolisis de Beta vulgaris L. con H 2 SO 4 . Se evaluo el efecto que tienen los parametros: agitacion, concentracion de acido, masa y temperatura sobre el grado de hidrolisis del sustrato. La masa se probo en el intervalo de 5 hasta 40 g y la agitacion de 100 a 250 rpm. La temperatura y el tiempo de reaccion fueron evaluados en el intervalo de 30 a 90 oC y de 2 a 6 h, respectivamente. El tamano de particula probado fue de 0.5 mm y para todos los casos el volumen de reaccion de 50 mL. A una velocidad de 150 rpm se tuvo mayor efecto de hidrolisis. Mediante comparacion de medias se determino que las concentraciones superiores a 0.5 N de H 2 SO 4 no tienen efecto significativo (p<0.05) sobre la liberacion de azucares totales. Con 10 g de sustrato en los medios de reaccion se obtuvo el mayor rendimiento de hidrolisis. La temperatura de 90 oC proporciono la ...

BioResources, 2016

Barley straw is a lignocellulosic biomass that can be used to obtain value-added products for ind... more Barley straw is a lignocellulosic biomass that can be used to obtain value-added products for industrial applications. Barley straw hydrolysis with sodium sulfite facilitates the production of lignosulfonates. In this work, the delignification process of barley straw by solubilizing lignin through sulfite method was studied. Response surface methodology and artificial neural network were used to develop predictive models for simulation and optimization of delignification process of barley straw. The influence of parameters over sulfite concentration (1.0 to 10.0%), particle size (8 to 20), and reaction time (30 to 90 min) on total percentage of solubilized material was investigated through a three level three factor (3 3) full factorial central composite design with the help of Matlab® ver. 8.1. The results show that particle size and sulfite concentration have the most significant effect on delignification process. Both techniques, response surface methodology and artificial neural networks, predicted the lignosulfonate yield adequately, although the artificial neural network technique produced a better fit (R 2 = 0.9825) against the response surface methodology (R 2 = 0.9290). Based on these findings, this study can be used as a guide to forecast the potential production of lignosulfonates from barley straw using different experimental conditions.

Mycological research, Jun 30, 2003

The strain Trametes sp. I-62 (CECT 20197) is a white-rot fungus with great potential for biotechn... more The strain Trametes sp. I-62 (CECT 20197) is a white-rot fungus with great potential for biotechnological applications in the fields of industrial waste water decolorization and clean up. Three laccase genes: lcc1, lcc2 and lcc3 have been cloned and sequenced from this basidiomycete. In this work, the coding regions of the corresponding cDNAs have been synthesized, cloned, and sequenced. They are 1563, 1563 and 1575 bp in length, respectively. Former putative intron/exon structures from genomic DNA are fully confirmed ...

Research in Microbiology, Mar 31, 2008

Wastewaters generated from the production of ethanol from sugar cane molasses may have detrimenta... more Wastewaters generated from the production of ethanol from sugar cane molasses may have detrimental effects on the environment due to their high chemical oxygen demand and dark brown color. The color is mainly associated with the presence of melanoidins, which are highly recalcitrant to biodegradation. We report here the induction of laccases by molasses wastewaters and molasses melanoidins in the basidiomycetous fungus Trametes sp. I-62. The time course of effluent decolorization and laccase activity in the culture supernatant of ...