Revista Mexicana de Ingeniería Química <div class="_4wyf">The Mexican Journal of Chemical Engineering &nbsp;(ISSN 1665-2738,&nbsp; issn-e: 2395-8472) publishes original research papers with the aim of promoting a rapid share of relevant research in various disciplines of Chemical Engineering and its interfaces with other enigineering disciplines. A volume is published each year and it consists of three issues, which are published every four months.&nbsp;</div> en-US <p>By publishing your paper in our journal you are also granting it the copyright of the information that it contains.</p> (Francisco J Valdes Parada) (Francisco J. Valdés-Parada) Thu, 14 Apr 2022 18:48:11 +0000 OJS 60 Hydrodynamics evaluation of an internal-loop airlift reactor with Newtonian and shear-thinning fluids: Experimentation vs CFD simulation <p>The hydrodynamics of an internal-loop airlift reactor was numerically and experimentally characterized. The gas holdup, liquid velocity, shear rate, flow pattern and volumetric oxygen transfer coefficient (<em>k<sub>L</sub>a</em>) were evaluated as a function of the air velocity and medium rheology. Tap water and CMC solutions were used as Newtonian and non-Newtonian fluids, respectively. The standard <em></em><em></em> model was employed for modeling turbulence, and unsteady three-dimensional simulations with the Euler–Euler model were performed. Gas holdup, liquid velocity and <em>k<sub>L</sub>a</em> measurements were performed for validating simulations. An increase in bubble coalescence and a decrease in <em>k<sub>L</sub>a</em> was observed with CMC solutions. The presence of recirculation loops inside the riser for CMC solutions is reported, which was not observed with tap water. The higher the CMC concentration, the larger the recirculation region seems to be. Results show that recirculation loops play a substantial role in the reactor’s hydrodynamic performance, and it turns out that the gas holdup in the riser increases with increasing the CMC concentration.</p> R. Guadarrama-Pérez, V.E. Márquez-Baños, J.J. Valencia-López, V. Sánchez-Vázquez, G. Martínez-De Jesús, J. Ramirez Munoz, M. Gutiérrez-Rojas ##submission.copyrightStatement## Mon, 18 Apr 2022 23:12:20 +0000 Importance of the C/N-ratio on biomass production and antimicrobial activity from marine bacteria Pseudoalteromonas sp <p>The main objective of this study was to investigate from the physiological point of view, the influence that nitrogen and carbon sources have on the biomass production and activity of the antimicrobial protein of <em>Pseudoalteromonas</em> sp. The impact of the change in the medium initial C/N-ratio on biomass production and antimicrobial activity against <em>S. aureus</em> MRSA was evaluated using two different carbon sources (glucose or citrate) and a fixed concentration of NH<sub>4</sub>Cl as a nitrogen source. The change in total nitrogen concentration in the medium was evaluated using organic or inorganic nitrogen sources (NH<sub>4</sub>Cl or yeast extract-peptone) while a fixed glucose concentrations was present.</p> <p>The results showed that the increase in C/N-ratio stimulated biomass production but inhibited antimicrobial activity regardless of the nature of the carbon source. Similarly, the biomass profile and antibiotic activity were dependent in the variation of low nitrogen total concentrations in the medium and especially at concentrations bigger than 3 g L<sup>-1</sup> negatively affected the antimicrobial activity. This indicated that the main factor affected the secondary metabolism of <em>Pseudoalteromonas</em> sp. was the nitrogen concentration over C/N-ratio.</p> R. López-Alcántara, J.L. Borges-Cu, J.E. Ramírez-Benítez, A. Garza-Ortiz, L.A. Núñez-Oreza, O.H. Hernández-Vázquez ##submission.copyrightStatement## Wed, 20 Apr 2022 14:25:53 +0000 Mathematical model to estimate volumetric oxygen transfer coefficient in bioreactors using conformable calculus <p>This work proposes a novel mathematical model based on time conformable derivative convective mass transfer equation to calculate the volumetric oxygen transfer coefficient (<em>k<sub>L</sub>a</em>) in a bioreactor. To validate the novel model, a full mixed-level experimental design was proposed with two factors: agitation speed and dispersed phase. The model employs the conformable derivate order operator (<em>α</em>) and the electrode constant (<em>k<sub>p</sub></em>), which changes with electrode use and the operating conditions of the bioreactor. The results show that when the viscosity increases and the agitation decreases, the value <em>α</em> increases, and vice versa. Therefore, <em>α</em> is a parameter that has a physical meaning in the process. The correlation coefficient of the proposed model with the experimental data (R<sup>2</sup> &gt; 0.985) is higher than the one obtained with conventional models. The Akaike information criterion determined that the proposed conformal model describes the experimental data by 59%, while the conventional models describe the experimental data by 25% and 15%. There are no reports of similar mathematical models that determine mass transfer coefficients in bioprocesses.</p> R. Melgarejo-Torres, D. Rosales-Mercado, M.A. Polo-Labarrios, G. Fernández-Anaya, M. Morales-Ibarría, S.B. Pérez-Vega, M.B. Arce-Vázquez, D.M. Palmerín-Carreño ##submission.copyrightStatement## Fri, 22 Apr 2022 20:04:04 +0000 Bioleaching of As from mine tailings using an autochthonous Bacillus cereus strain <p>Contamination of heavy metals has been a serious environmental problem due to increasing anthropogenic activities such as mining, smelting, livestock, landfills, waste dumps, and agriculture. Bioleaching experiments were conducted using native <em>Bacillus cereus</em> MAMPE19 BCG, isolated and characterized from previous research, to test removal of arsenic (As) from actual mining waste. Mineralogical characterization by XRD was performed to identify mineral associations with As. The experimental design included a bioleaching system with agitated flasks (triplicate) and the effects of pH (5, 7, and 9) and pulp density (10, 15, and 20%) were evaluated. Finally, based on the results of the ANOVA, the system that achieved the highest percentage of As dissolution was selected and scaled to a stirred tank bioreactor. The composition of the mineral was mainly calcite (CaCO<sub>3</sub>), gismondine (CaAl<sub>2</sub>Si<sub>2</sub>O<sub>8</sub>·4(H<sub>2</sub>O)), akermanite (Ca<sub>2</sub>MgSi<sub>2</sub>O<sub>7</sub>), and silicon oxide (SiO<sub>2</sub>). Native <em>Bacillus</em> <em>cereus</em> dissolved 40.6 ± 4.9 and 37.4 ± 2.7 % of As in 10 d, in agitated flasks at a pH of 5 and a pulp density of 10 and 15%, respectively; and a 27.5 ± 2.9% dissolution of As was achieved in the stirred tank bioreactor at pH 5 and pulp density of 15%, supported by significant statistical differences.</p> A.M. Cabrales-González, M.A. Martínez-Prado, D.M. Núñez-Ramírez, E.R. Meléndez-Sánchez, L. Medina-Torres, R. Parra-Saldivar ##submission.copyrightStatement## Tue, 26 Apr 2022 14:38:01 +0000 Valorisation of rice husks and bean straws through fuel pellets production: an experimental and modelling approach <p>Worldwide, agricultural wastes represent an environmental problem due to their high volumes and inadequate disposal. Due to this, valorization of these wastes has been studied, being the production of biofuels a promising option. In particular, rice husks were proposed to produce fuel pellets, buy they do not fulfill the ISO 17225-6 standard due to its elevated ash content; thus, it is required to mix them with other wastes available in the same region. In Mexican states where rice is produced also bean is cultivated, whose residues are not used and have an elevated content of volatile solids. Therefore, the objective of this research is to produce fuel pellets from rice husk and bean straws that meet ISO 17225-6 standard. For this, the densification was carried out using three levels of moisture content and mixing ratios of the biomasses. Based on the experimental data, optimal densification conditions were found through a response surface analysis. Results show that fuel pellets produced from bean straw (90%) and rice husk (10%) with 15.0% of moisture content fulfill ISO 17225-6 standard.&nbsp; At these conditions, fuel pellets have calorific power of 3,645.78 kcal/kg, 6.98 ash, 9.76% final moisture, 610.78 kg/m<sup>3</sup> bulk density, and 99.51% durability.</p> C. Gutierrez-Antonio, N. Hernández-Neri, J.F. García-Trejo, A.A. Feregrino-Pérez, M. Toledano-Ayala ##submission.copyrightStatement## Thu, 14 Apr 2022 18:42:42 +0000 Use of freeze-drying and convection as drying methods of the xoconostle by-product and the effect on its antioxidant properties <p>In this study, the influence of the drying method (lyophilization and convection) on the techno-functional and antioxidant properties of the by-product of xoconostle cv. Cuaresmeño (<em>Opuntia matudae</em>) was evaluated. During convection drying, the effect of the temperature (60, 70 and 80 °C) was evaluated, resulting in drying times of 195, 165 and 120 minutes, respectively. The influence of the temperature on the equilibrium humidity was determined through the drying kinetics, which were affected by increasing the temperature from 60 to 80°C. The drying time for the by-product decreased, and equilibrium humidities of 0.04, 0.03 and 0.02 g water/g dry sample were reached for 60, 70 and 80 °C, respectively. Fick's second law was used along the experiments to determine the effective diffusivity, which ranged from 4.788 E<sup>-10</sup>–8.109 E<sup>-10</sup> m<sup>2</sup>/s for the evaluated temperatures. Convective drying at 60°C proved to be a suitable alternative for the conservation of antioxidant capacity (88.07 ± 0.38% 2,2-diphenyl-1-picrylhydrazyl (DPPH) inhibition) compared to drying at 70 and 80°C. These were 8% higher compared to the results for freeze drying. However, convective drying at 60°C is more convenient for the xoconostle by-products due to the cost-benefit ratio.</p> A.A. Morales-Tapia, F.E. González-Jiménez, G. Vivar-Vera, J.A. Del Ángel-Zumaya, M. Reyes-Reyes, L. Alamilla-Beltrán, J.E. Barojas-Zavaleta, B.L. Cooper-Bribiesca, J. Jiménez-Guzmán ##submission.copyrightStatement## Tue, 19 Apr 2022 04:02:09 +0000 Modification of the nutraceutical characteristics of jalapeño chili peppers in response to hormones <p>Pot experiments were conducted in a greenhouse of the National Technological of Mexico in Celaya during two summer seasons, in 2019 and 2020, to study the changes in the concentration of nutraceutical compounds in jalapeño chili pepper in response to two phytohormones (gibberellic acid and auxins) and two drying processes (lyophilization and drying by convection oven). Jalapeño chili pepper (<em>Capsicum annuum</em> L.) plants were treated with the phytohormones separately (gibberellic acid, 5 mM solution and auxins (2 mL/L solution)) and mixed together. The obtained results indicated that the freeze-drying process significantly preserved the concentration of nutraceutical compounds and antioxidant activity. The individual application of phytohormones led to significant increases in the concentrations of all nutraceutical compounds and antioxidant activity in the jalapeño chili peppers. However, an antagonist effect of the phytohormone mixture on jalapeño chili pepper production was observed, and for this reason, no jalapeño chili pepper samples were obtained. In conclusion, drying and phytohormonal treatment influence the preservation of nutraceutical compounds and antioxidant activity.</p> H. Medina, L. González-Cruz, R.G. Olan-Villegas, G. Acosta-García, N.L. Flores-Martínez, A. Bernardino-Nicanor ##submission.copyrightStatement## Thu, 21 Apr 2022 02:52:58 +0000 Anaerobic digestion of agro-industrial waste: Anaerobic lagoons in Latin America <p>The valorization of agro-industrial wastes (AW) by means of waste-to-energy strategies through anaerobic digestion (AD) is a reality in developed countries. In Latin America, there are different problems in the management of AW from intensive livestock farming. This study aims to provide a pseudo-radiography of AD management systems with a focus on anaerobic lagoons in Latin America (LATAM). Using data science, quantitative and qualitative data from 1003 scientific papers were synthesized and analyzed to form a database; which allowed evaluation of the congruence of the scientific research with the real problems of LATAM management. The results showed that anaerobic lagoons in the region are the main AW management systems (mainly bovine and swine manure) and that scientific research in this sector does not address the related problems. 38 types of inhibition phenomena with a total of 5264 mentions were addressed in the database. Nitrogen-related AR inhibition phenomena represented 21% of the incidences in this study, besides being the most significant phenomenon in anaerobic lagoons in LATAM</p> U. Galván-Arzola, L.R. Miramontes-Martínez, C. Escamilla-Alvarado, J.E. Botello-Álvarez, M.M. Alcalá-Rodríguez, R. Valencia-Vázquez, P. Rivas-García ##submission.copyrightStatement## Fri, 15 Apr 2022 02:11:53 +0000 Effect of drying on the extraction yield of Luma chequen (Molina) A. Gray essential oil <p>This work studies the effect of drying at 40 °C of the leaves and stems of the species <em>Luma chequen (Molina) A. Gray </em>on the extraction yield of its essential oil by steam distillation at a pilot scale. From the micromorphological evaluation at the moisture levels fresh state (72±1%), critical moisture (24±1%) and equilibrium moisture (8.2±0.5%), it is found that the tissues fold, the secretory cavities thin out, according to the lacunarity, the microstructure of the plant material exhibits greater uniformity at the critical moisture. For the extraction tests 18 levels of moisture were considered, keeping the packing factor at 54 Kg/m<sup>3</sup>. The maximum yield of 0.52 ± 0.01% <em>(v/w)</em> was reached when the moisture of the material was 22±1%, very close to the critical moisture. A first-order model provided a suitable fit to the extraction kinetic data for samples with different humidity levels. Based on the evaporation rate equation, a description of the microstructure of the material and the drying conditions, a model was developed which shows the evaporation mechanism to be dominant in both the drying process and in the extraction of essential oil.</p> M.E. Borja-Málaga, A. Jiménez-Ochoa, E. Medina-de Miranda, F.A. Escobedo-Vargas ##submission.copyrightStatement## Tue, 19 Apr 2022 03:48:00 +0000