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142 results on '"González-Álvarez, V."'

26. Ionic liquid-water mixtures enhance pretreatment and anaerobic digestion of agave bagasse

Author

Pérez-Pimienta, JA, Pérez-Pimienta, JA, García-López, RM, Méndez-Acosta, HO, González-Álvarez, V, Simmons, BA, Méndoza-Pérez, JA, Arreola-Vargas, J, Pérez-Pimienta, JA, Pérez-Pimienta, JA, García-López, RM, Méndez-Acosta, HO, González-Álvarez, V, Simmons, BA, Méndoza-Pérez, JA, and Arreola-Vargas, J

Abstract

Agave bagasse (AB), a byproduct of tequila production, is a waste generated in large quantities and an emerging alternative for biofuels production. Nevertheless, the use of lignocellulosic biomass for this purpose requires a pretreatment that maximizes its degradation and utilization. Although there are several pretreatment types, using ionic liquids (IL) has become attractive due to its ability to dissolve the lignocellulosic biomass under mild conditions of time and temperature. As a drawback are the high cost of IL's and their high viscosity; thus mixing them with water is a way to overcome these hindrances. This work aimed to evaluate the effect of pretreatment with three diluted ILs on the A. tequilana bagasse structure and sugars production, as well as the potential of the enzymatic hydrolysate to produce methane in batch mode. The evaluated ILs were: 1-ethyl-3-methylimidazolium acetate [Emim][OAc], choline lysinate [Ch][Lys] and ethanolamine acetate [EOA][OAc]. The results showed that the IL with the best performance was [Ch][Lys], which not only offered the highest yields of sugar production (0.57 ± 0.03 g total sugars / g bagasse) but also, it is possible to use it at 30 % in a mix with water obtaining similar yields as with pure IL. Enzymatic hydrolysis of IL pretreated AB achieved 50.7 kg sugars and 49.3 kg of sugars for 90 %-[Ch][Lys] and 30 %-[Ch][Lys], respectively per 100 kg of untreated biomass. The enzymatic hydrolysate from the 30 %-[Ch][Lys] pretreated AB was able to achieve 0.28 L CH4/g CODfed, demonstrating that both sugar and methane yields are maintained when pure or 30 %-[Ch][Lys] are used for pretreatment, representing a step forward towards process feasibility.

Published
2021

45. A simple microbial electrochemical cell model and dynamic analysis towards control design.

Author

Flores-Estrella, R. A., Rodríguez-Valenzuela, G., Ramírez-Landeros, J. R., Alcaraz-González, V., and González-Álvarez, V.

Subjects
MICROBIAL cells, DYNAMIC models, ORDINARY differential equations, NONLINEAR differential equations, MICROORGANISM populations, ELECTRIC batteries
Abstract

In this article, a mathematical microbial electrochemical cell (MEC) dynamic model is proposed. The model is derived from mass balances of a continuous flow MEC system which consists of two interconnected chambers. The system is described by a set of nonlinear ordinary differential equations (ODEs) that describes: (i) the competition of anodophilic and methanogenic microbial populations for a common substrate and; (ii) biomass growth and retention in the anodic compartment. Open loop behavior is evaluated via numerical simulations. The model is suitable both for process optimization and online control applications. Parametric sensitivity, stability, and convergence properties of the proposed model are also addressed in this article. [ABSTRACT FROM AUTHOR]

Published
2020
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46. EFFECT OF PLASMA ENERGY ON THE ANTIOXIDANT ACTIVITY, TOTAL POLYPHENOLS AND FUNGAL VIABILITY IN CHAMOMILE (MATRICARIA CHAMOMILLA) AND CINNAMON (CINNAMOMUM ZEYLANICUM)

Author

Solís-Pacheco J.R., Villanueva-Tiburcio J.E., Peña-Eguiluz R., González-Reynoso O., Cabrera-Díaz E., González-Álvarez V., Aguilar-Uscanga, and B.R.

Subjects
Plasma, food safety, antioxidants, yeasts and molds, phenolic content, lcsh:QR1-502, lcsh:Microbiology
Abstract

The plasma energy is a collection of free particles with positive and negative charges and has demonstrated to be a good prospect for food preservation. The aim of this study was to evaluate the effect of plasma energy on the antioxidant activity, total polyphenol content and yeasts and molds counts in chamomile and cinnamon powder samples treated at 650, 750 and 850 volts for 0, 1, 3 ,5 7 and10 min. Total counts of yeasts and molds in chamomile and cinamon powder samples were determined before and after each treatment with plasma energy. The enumeration was conducted on potatoe dextrose agar suplemented with 0.6% Bengal rose and 2% ampicillin. The antioxidant activity and total polyphenol content were also analyzed. The results showed that plasma exposure on chamomile and cinnamon powder at 850V for 10 minutes significantly reduced (p

Published
2013

47. Enteropathogens in Holstein calves with diarrhea during the first five weeks of age in México.

Author

Delgado-González, R. A., Meza-Herrera, C. A., González-Álvarez, V. H., Alvarado-Espino, A. S., Contreras-Villareal, V., Gaytán-Alemán, L. R., Arellano-Rodríguez, G., and Véliz-Deras, F. G.

Subjects
ROTAVIRUSES, CRYPTOSPORIDIUM, CALVES, MIXED infections, DIARRHEA, SALMONELLA
Abstract

The aim was to assess the prevalence of etiologic agents of diarrhea in single and mixed infections and their relationship with age in Holstein calves. Fecal diarrheic samples (n=90) were taken to determine the causative agent (E. coli (K99), Salmonella spp., Cryptosporidium spp., Coronavirus, and Rotavirus). Samples tested were positive at least to one pathogen (87.7%), most of the positive cases were mixed infections (62%; P<0.01); from these, affected by two (59%) and by three or more agents (41%; P=0.07). Cryptosporidium spp. and Rotavirus were the most common agents and most of infections occurred during the first two weeks of age. [ABSTRACT FROM AUTHOR]

Published
2019
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48. Active prokaryotic population dynamics exhibit high correlation to reactor performance during methane production from acid hydrolysates of Agave tequilana var. azul bagasse.

Author

Snell‐Castro, R., Méndez‐Acosta, H.O., Arreola‐Vargas, J., González‐Álvarez, V., Pintado‐González, M., González‐Morales, M.T., and Godon, J.J.

Subjects
ARCHAEBACTERIA, AGAVES, BIOGAS production, METHANOGENS, CHEMICAL oxygen demand
Abstract

Aims: The purpose of this study was to apply cDNA approach for the characterization of active prokaryotic community to understand microbial scenarios and performance of an AnSBR digester fed with acid hydrolysates of Agave tequilana var. azul bagasse (ATAB). Methods and Results: The digester was implemented for methane production under organic loading rate (OLR) disturbances to correlate physicochemical variables with changes in abundance, diversity and population dynamics of active Bacteria and Archaea by principal components analysis (PCA). Results indicated that methane yield increased as well as active syntrophic relationships for interspecies hydrogen/formate (Anaerolinaceae‐Methanobacterium beijingense) and acetate (Anaerolinaceae‐Methanosaeta concilii) transfers at 8 g‐COD l−1 day−1. However, methane yield was negatively affected at 16 g‐COD l−1 day−1 due to the competition for acetate by active Desulfovibrio marrakechensis and volatile fatty acids inhibition. Conclusions: Microbial scenarios obtained by PCA correlations indicated that methane production from acid hydrolysates of ATAB was feasible at 8 g‐COD l−1 day−1. The digester operation at higher OLR only favoured methanogenesis by the hydrogenotrophic pathway. Significance and Impact of the Study: Only cDNA analysis showed Archaea population dynamics, exhibiting high correlation with physicochemical variables towards the understanding of the methanogenic digester performance during OLR disturbances. [ABSTRACT FROM AUTHOR]

Published
2019
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