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> Academia Mexicana de Investigación y Docencia en Ingeniería Química en-US Revista Mexicana de Ingeniería Química 1665-2738 <p>By publishing your paper in our journal you are also granting it the copyright of the information that it contains.</p> In memoriam Mariano Gutiérrez Rojas <p>This is an editorial article dedicated to honor the memory of Dr.&nbsp;Mariano Gutiérrez Rojas</p> Gustavo Viniegra González ##submission.copyrightStatement## 2020-07-23 2020-07-23 19 Sup. 1 10.24275/rmiq/Ed1924 Composting a digestate from the organic fraction of urban solid wastes <p>A biosolid was produced from the composted digestate of the organic fraction of urban solid wastes (OFUSW). During a first hydrolytic-acidogenic stage, the milled OFUSW mass is transformed into volatile fatty acids and other soluble or suspended substances in the leachate while the residual solids constitute the digestate.</p> <p>A biosolid was produced from the composted digestate of the organic fraction of urban solid wastes (OFUSW). During a first hydrolytic-acidogenic stage, the milled OFUSW mass is transformed into volatile fatty acids and other soluble or suspended substances in the leachate while the residual solids constitute the digestate. To obtain a composting mass (CM) with a C/N between 25 and 35 and a matrix to allow aeration, mixtures of digestate (fD), OFUSW (fF) and sawdust (fS) were prepared using a simplex centroid design. Results were adjusted to a multiple regression model with volatile solids degradation efficiency (ηVS) as a response variable. It was found that the operation zone with the highest ηVS, were CM with the following compositions: <em>f</em>D: 0.425-0.625, <em>f</em>F: 0.275-0.450; and <em>f</em>S: 0.1-0.15. Three assays were carried out in a bench scale reactor, the final biosolids had a pH = 7.5, a C/N = 15 and a germination index (GI) = 84%. A linear correlation between ηvs and CO2 production was proposed for process control. A rapid CM stabilization was reached, up to ηVS = 35% in 12 days and the biosolids with high GI, can be used to improve soils.</p> R. Espinosa-Salgado G. Saucedo-Castañeda O. Monroy-Hermosillo ##submission.copyrightStatement## 2020-04-01 2020-04-01 19 Sup. 1 1 8 10.24275/rmiq/IA1236 Industrial wastewater treatment by anaerobic digestion using a solar heater as renewable energy for temperature-control <p>The clean energies have been the only renewable energies that are capable to replace the use of fossil fuels. The use of clean energies in Wastewater Treatments Plants would decrease the operating costs. In the present work, a solar heater of 8 tubes was used for controlling the temperature of an UASB reactor in order to treat a mixture of industrial wastewater under anaerobic digestion. The reactor was operated at three temperatures (16, 20, and 30 ºC), at organic loading rate of 11 g COD/L-d, HRT of 6 h, and during a period of 100 days. In addition, the effect of a co-substrate on COD consumption was evaluated, in batch cultures. In the steady-state, COD removal efficiencies were 8.6, 20, and 40 %, for 16, 20, and 30 ºC, respectively. Increasing the temperature enhanced the methane production, achieving in average 257 ± 8.6 ml CH<sub>4</sub>/ g COD removed. In batch cultures, 200 and 400 mg glucose/L used as co-substrate significantly improved the removal and COD consumption rates. Finally, a solar heater might be feasible and economical technology for temperature-control of an UASB reactor in order to improve the organic matter removal. &nbsp;</p> M.D. Gómez-Paredes I.A. Hernández-Rodríguez J. López-Ortega G. González-Blanco R. Beristain-Cardoso ##submission.copyrightStatement## 2020-07-02 2020-07-02 19 Sup. 1 9 16 10.24275/rmiq/IA1853 Acidogenesis/methanogenesis from acid cheese whey in hybrid-UASB reactors <p>The cheese industry produces residues, such as acid cheese whey; this by-product has a high organic-matter concentration and other nutrients that are severe environmental contaminants. The aim of this study was to evaluate the acidogenesis/methanogenesis of acid cheese whey with short Hydraulic Retention Times (HRT) in Hybrid-UASB reactors, following the organic matter, ammonia, and orthophosphate evolution. The acidogenic reactor was operated at HRT of 0.5 days, while for the methanogenic reactor, ranged from 1‒2 days; both reactors were operated in series. Results show that the overall HRT of 1.5 days allowed optimal removal (89‒96.8%) with organic loading rates between 2.5 and 10.7 g COD/L-d, while at 14.2‒24.9 g COD/L-d best results were found at 2.5 days of overall HRT. Highest methane productivity ranged from 0.99‒1.15 L<sub>CH4</sub>/L<sub>Reactor</sub>-d (0.238‒0.308 L<sub>CH4</sub>/g COD<sub>degraded</sub>). Ammonia formation was only significant in methanogenesis (85 mg/L), while orthophosphates showed no change throughout all the process. In conclusion Hybrid-UASB reactors operated at short HRT were suitable for the acidogenesis/methanogenesis of this wastewater. Furthermore, methane can be used for energy generation, and ammonia and orthophosphate might be employed for the development of high value-added products.</p> K.N. Cárdenas-Medina M.C. Fajardo-Ortiz B.S. Schettino-Bermúdez M.A. Meraz-Rodríguez P. Castilla-Hernández ##submission.copyrightStatement## 2020-07-21 2020-07-21 19 Sup. 1 17 27 10.24275/rmiq/IA1420 Anaerobic digestion inhibition indicators and control strategies in processes treating industrial wastewater and wastes <p>Based on a literature review, a set of inhibition indicators is presented for each stage of anaerobic digestion according to the behavior of certain parameters: the reduction of the total COD/soluble COD ratio; the low volatile fatty acids (VFA) production; the accumulation of VFA and low acetate production; and the low methane production. Moreover, we present several preventive and recovery strategies for each stage considering the detected inhibition indicator. Some of the preventive strategies are the acclimation of microorganisms to degrade organic-matter in the presence of certain inhibitors, the enrichment of the inoculum with various additives (e.g., sulfate-reducing bacteria, electron donors, mineral adsorbents or nutrients), the dilution of the influent, and the prior removal of the inhibitors. Some of the proposed recovery strategies are the reduction of the inhibitor concentration by removal strategies (e.g., precipitation, adsorption, and sulfate-reduction), intermittent feeding, and decrease of the total influent volume. Lastly, we present the challenges and future perspectives of applying the inhibition indicators and control strategies, e.g., the importance of developing straightforward and low-cost technologies for the monitoring of the various parameters or even for the design of anaerobic treatment systems, including an automatized monitoring system of the parameters proposed as inhibition indicators.</p> A. Serrano-Meza M.A. Garzón-Zúñiga B.E. Barragán-Huerta E.B. Estrada-Arriaga N. Almaraz-Abarca J.G. García-Olivares ##submission.copyrightStatement## 2020-04-23 2020-04-23 19 Sup. 1 29 44 10.24275/rmiq/IA1221 Role of Eisenia foetida in the degradation of profenofos in presence of native bacterial communities <p>The use of profenofos (PFF) increased due to its effectiveness against pests resistant to other organophosphates (OP). Its presence in the environment could produce acute or chronic poisoning for people who use it for daily agricultural activities as well as for people who get in contact with polluted soil, water, air or food. In this context, proposing alternatives to accelerate OP degradation processes is important. Therefore, the objective of the present study was to evaluate for 28 days the degradation process of PFF in soils with 50 mg PFF/kg (pH = 7.20 + / - 0.31) using <em>Eisenia foetida</em> (EF) and native bacteria (NB). The "control group" showed a PFF degradation of 52.95 +/- 1.69% in sterilized soils. NB achieved a degradation of 63.60 +/- 3.27%, EF degraded PFF by 72.65 +/- 1.92% and the combination of EF and NB, 79.21 +/- 1.79%. Bacteria with potential PFF degradation capacity were isolated and identified as <em>Klebsiella oxytoca</em> and <em>Pseudomonas aeruginosa</em>. It was shown that EF play an important role by accelerating the degradation of PFF in soils, presenting a possible synergy with <em>Klebsiella oxytoca</em> and <em>Pseudomonas aeruginosa</em>.</p> E.G. Gonzales-Condori S.A. Ramírez-Revilla J.A. Villanueva-Salas ##submission.copyrightStatement## 2020-06-17 2020-06-17 19 Sup. 1 45 57 10.24275/rmiq/IA1505 On the sequestration of polycyclic aromatic hydrocarbons in aged artificial soil <p>The fate of polycyclic aromatic hydrocarbons is a major environmental concern that has attracted much attention in current literature. The physicochemical properties of contaminants, along with soil characteristics and ageing, translate into an unusual sorption that leads to high sequestration and low bioavailability. In the present study, fresh (non-sterile) and aged (sterile) synthetic soils (sand-perlite 1:1 v/v) were characterized and spiked (hexadecane, phenanthrene and pyrene 2:1:0.5) to evaluate sequestration extents. Hydrocarbons extraction differed for sand and perlite in fresh samples, on the contrary, the artificial ageing process affected equally the extraction in the synthetic soil components. In the synthetic soil, the extractability of hexadecane and phenanthrene were 80% and 60%, respectively, in fresh samples, but for both hydrocarbons it was only 20% in aged samples. Pyrene extractability was not affected by the components of the synthetic soil or by ageing, and this may be related to an in-situ crystallisation process. The characteristics of the soil and its contaminants, coupled with long-term interactions, significantly modified the PAHs environmental fate, leading to the formation of non-extractable residues, also known as sequestered contaminants. This study expands current knowledge about the fate of these contaminants and should serve as motivation for further experimental and theoretical research on this subject.</p> P. Gómez-Flores M. Gutiérrez-Rojas E.A. Motolinia-Alcántara G.M. Ontiveros-Campos G.M. Trejo-Aguilar ##submission.copyrightStatement## 2020-06-27 2020-06-27 19 Sup. 1 59 68 The fungus Lewia sp. alleviates the oxidative stress in F. arundinacea during the endophyte-assisted phytoremediation of hydrocarbons <p>Due to their mutagenic and carcinogenic effects, polycyclic aromatic hydrocarbons (PAH) have gathered significant environmental concern. Endophyte-assisted phytoremediation is a feasible alternative to reduce PAH pollution in soils more efficiently than plants or microorganisms individually. Endophytes can improve the growth, fitness, and antioxidant system of their hosts, especially under stress, including contamination. In this context, this study aimed to assess the influence of <em>Lewia</em> sp. on antioxidant defense and the hydrocarbon removal by <em>F. arundinacea</em> during 45 days of exposure to a hydrocarbon mixture. Plant growth and lipid peroxidation (LPO), as well as superoxide dismutase (SOD), peroxidase (POD) and glutathione S-transferase (GST) activities were determined in a kinetic assay. The association significantly improved the hydrocarbon removal over a 45-day period, while promoting plant growth and controlling oxidative damage, particularly in the roots. The root antioxidant system in <em>F. arundinacea</em> is itself effective in counteracting the phytotoxicity of direct contact with hydrocarbons. However, <em>Lewia</em> sp. controls LPO in the roots, which may be a consequence of the fungus's own antioxidant system, involving the coordinated activity of SOD and POD. Once the endophytic association is established, it can be applied to phytoremediate PAH-polluted soils during a minimum period of 45 days.</p> C. Mendarte-Alquisira M. Gutiérrez-Rojas T. Volke-Sepúlveda ##submission.copyrightStatement## 2020-06-26 2020-06-26 19 Sup. 1 69 80 10.24275/rmiq/Bio1547 Biodigester with mixing by hydraulic recirculation of the wastewater on biogas production: Fundamentals in the design and scaling by a dimensional analysis <p>In the present work were established fundamentals relations and criteria for characterization and scaling on the biogas production of a biodigester operated with mixing by hydraulic recirculation of the wastewater. An ovoid geometry for the biodigester was chosen, and with the scale factor and geometric relationships were developed equations to scaling geometrically the biodigester, building the <em>biodigester.slx</em> program for the calculates in Simulink (Matlab® software). Seventeen process variables were identified and by means of the dimensional analysis accord to the p theorem of Vaschy-Buckingham were correlated to generate the dimensionless numbers of Geometry, Reynolds, Power, Recirculation, and Damköhler I. The dimensionless functions and dimensionless numbers allowed developing expressions for power consumption and the biogas production volumetric rate from the recirculation velocity and hydraulic recirculation rate, respectively. The above was done considering the next three aspects, the behavior of the wastewater as non-Newtonian fluid, the sludge and manure concentration, and the mixing effect by hydraulic recirculation of the wastewater. Further, from the similitude principles of geometry, kinematic, dynamic, and chemical were established criteria and equations for scaling of recirculation velocity, the power consumption, and the biogas production volumetric rate. The work is a platform to study biogas production by anaerobic digestion in biodigesters operated by batch with mixing by hydraulic recirculation of the wastewater.</p> S.G. Monroy-Oropeza A. Jiménez-González M. Gutiérrez-Rojas S.A. Medina-Moreno ##submission.copyrightStatement## 2020-05-28 2020-05-28 19 Sup. 1 81 99 10.24275/rmiq/Bio1545 Bioreactors for remediation of hydrocarbons in rivers and lagoons of San Luis Potosí <p>The polluting hydrocarbons in water bodies of the state of San Luis Potosí were evaluated and determined in June 2019, to choose a representative carbon source for the airlift bioreactor. The sampling points were Chajir Lagoon, Puente de Dios, Tampaón River and Media Luna Lagoon, and aliphatic hydrocarbons with a carbon number between C8-C32 were found. We reported high concentrations of pollutants, such as eicosane (up to 2,603.22 ± 1,202.09 mg L<sup>-1</sup>) and heneicosane (up to 3,971.21 ± 2,260.45 mg L<sup>-1</sup>). The airlift bioreactor was designed based on hydrodynamic parameters: holdup gas (εG), Sauter mean diameter (d32) and Reynolds number (Re) that increased with the superficial gas velocity (Ug), both in the riser zone and downcomer zone and from Ug = 1.92 cm s<sup>-1</sup>, mixing and mass transfer are favoured in a 2 L airlift reactor. Also, the hydrodynamic parameters evaluated were higher in the riser zone. Furthermore, the consortium isolated by the Gutiérrez-Rojas working group composed of <em>Xanthomonas</em> sp., <em>Acinetobacter</em> <em>Bouvetii</em>, <em>Shewanella</em> Sp., and <em>Defluvibacter</em> <em>lusatiensis</em>, was able to consume 98.21% of the initial diesel concentration (13,000 mg L<sup>-1</sup>). The airlift bioreactor evaluated in the investigation proved to be workable for the remediation of water bodies.</p> E.J. Sandoval-Herazo G. Espinosa-Reyes M.R. Vallejo-Perez R. Flores-Ramirez F. Pérez-Vazquez N.U. García-Cruz M.A. Lizardi-Jiménez ##submission.copyrightStatement## 2020-05-24 2020-05-24 19 Sup. 1 101 110 10.24275/rmiq/Bio1470 Biotechnological processes improved with electric fields: the importance of operational parameters selection <p>The imposition of electric fields on a porous media has been a useful tool for biotechnological processes improvement, mainly in environmental engineering; however, the success in its reproducibility depends on the standardized methodology rather than empirical results. This work describes three experimental cases: <em>Aspergillus brasiliensis</em> attached to perlite for emulsifier protein production, <em>Metarhizium anisopliae</em> as a biologic control of insect pests and the characterization of a hydrocarbon contaminated soil. The standardized methodology is independent of the biotechnological purposes and consists of: (i) establishment of current density in which porous media behaved as an electric resistance (0–2.5, 0-0.6 and 0-0.85 mA cm<sup>-2</sup>, for perlite, rice-corn mixture and soil, respectively). (ii) establishment of a current density in which cell potential is constant, to make sure that no gradient of nutrients concentration is formed and (iii) pH gradient evaluation as a consequence of water oxidation/reduction electrochemical reactions and the charge transport capability across the porous media. As a result of the aforementioned standardization three sections of packed porous media on electrochemical cell would be obtained: anodic (acidified), middle (neutral) and cathodic (alkalinized), which have different physicochemical properties and promote also different metabolic responses when they are used as supports for solid-state culture.</p> P. Gómez-Flores N. Velasco-Álvarez I. González V. Sánchez-Vázquez ##submission.copyrightStatement## 2020-07-06 2020-07-06 19 Sup. 1 111 121 10.24275/rmiq/Bio1689 Increase in the mortality of the entomopathogenic fungus Metarhizium anisopliae due to the application of an electric field during conidiation <p>The effects of an electric field on conidia production by <em>Metarhizium anisopliae</em> in solid state culture were determined. A 450-mL electrochemical cell (EC) with titanium ruthenium-oxide coated electrodes and packed with a mixture of rice:corn stubble, was inoculated with 1x10<sup>6</sup> conidia (g of initial dry support)<sup>-1</sup> and incubated for 8 days (30ºC). Four days after starting the culture, a current density of 0.09 mA/cm<sup>2 </sup>was applied for 24 h. The moisture kept constant (75%), with and without electric field. With electric field, conidiation (4.9x10<sup>8</sup> ± 3.7x10<sup>7</sup> conidia (g of initial dry support)<sup>-1</sup>) did not show significant differences, but their viability and germination (67 and 45%, respectively) were lower than in the non-perturbated conidia. Total mortality of <em>Tenebrio molitor</em> larvae provoked by conidia produced in presence of the electric field was 40% higher compared to that provoked by the conidia control. The study showed that the application of electric field improving the conidial infectivity. This new approach is susceptible to be optimized to other fungi for biological control with the purpose of improving field performance and further investigations on the modification of cellular mechanisms by the electric field stimuli.</p> D. Rodriguez-Gomez L. Garate-Velez A.L. Morales-Piña M. Gutiérrez-Rojas N. Velasco-Alvarez ##submission.copyrightStatement## 2020-07-20 2020-07-20 19 Sup. 1 123 133 10.24275/rmiq/Bio1601 Wet processing coffee waste as an alternative to produce extracts with antifungal activity: In vitro and in vivo valorization <p>Wet coffee waste (WCW) generated by the wet benefit process of the coffee, is mainly made up of coffee pulp and husk, and has been scarcely studied and reutilized. Therefore, the aim of this work was to investigate the <em>in vitro</em> and <em>in vivo</em> antifungal activity of an optimized WCW ethanolic-extract (OE) obtained by ultrasonication (amplitude 70%, sonication time 45 min). OE had total phenolic content of 33.8 mg gallic acid equivalents/g and antioxidant activity of 1790.1 µmol Trolox equivalents/g. OE showed a potent <em>in vitro </em>antifungal activity against <em>A. niger</em>, <em>B. cinerea</em> and<em> R.</em><em> stolonifer </em>equivalent or superior to that of commercial synthetic carbendazim. Strawberries were wounded and inoculated with the three fungi for <em>in vivo </em>assays. After 5 d of inoculation, percentage of wounds presenting mold growth was of 16.7% (400 µg/mL of OE) and 38.2% (1000 µg/mL of carbendazim) for <em>A. niger</em>, and of 36.1% for <em>B. cinerea</em> and of 50.12% for<em> R. stolonifer</em> (2000 µg/mL of OE) compared to the 38.2% and 51.2% (1000 µg/mL of carbendazim), respectively. The efficient antifungal activity of OE can be mainly attributed to its majoritarian compounds chlorogenic acid (14.19 mg/g) and caffeic acid (1.18 mg/g), which represented 89.83% of the identified.</p> C. Lobato-Calleros S. Alvarado-Ambriz L. Hernández-Rodríguez E.J. Vernon-Carter ##submission.copyrightStatement## 2020-05-24 2020-05-24 19 Sup. 1 135 149 10.24275/rmiq/Bio1612 Tolerance and accumulation of lead by endophytic association between Festuca arundinacea and Lewia sp. <p>Endophyte assisted phytoremediation is an environmentally friendly alternative for the remediation and treatment of soils contaminated with heavy metals. The effect of the association between endophytic fungus (<em>Lewia</em> sp.) and <em>Festuca arundinacea</em> on the tolerance and accumulation of lead (Pb) was studied after 45 days of culture in contaminated soil. The tolerance to 2,500 mg Pb Kg<sup>-1</sup> was quantified by biomass production and the accumulation of lead in shoots and roots. The phytoremediation potential was quantified by estimating the tolerance index (TI), the bioaccumulation factor (BCF) and translocation factor (TF). The Pb accumulation in roots (14 ± 4.2 mg g<sup>-1</sup>), was 3-fold higher in plants inoculated in comparison with only plant (3.73 ± 0.64 mg g<sup>-1</sup>); The TI was 0.76 and 0.56, the BCF was 0.31 and 0.23 for inoculated and non-inoculated plants, respectively. The TF was not detected in both cases, indicates that when working with this association there is not risk of trophic transfer of lead, according to parameters obtained, <em>Lewia</em> sp. improved growth and tolerance of <em>F. arundinacea</em> in Pb contaminated soil. The association between <em>F. arundinacea-Lewia</em> sp. can be considered a promising endophytic association for the remediation <em>in situ</em>.</p> C.S. Ortega-Aguilar M. Gutiérrez-Rojas A. Cruz-Hernández ##submission.copyrightStatement## 2020-05-29 2020-05-29 19 Sup. 1 151 160 10.24275/rmiq/Bio1649 Omega fatty acids production in an isolated native Chlorella sp. from northeast Mexico with improved growth using urine as nutritive medium <p>The production of essential fatty acids (Omega 3, 6, 9) from microalgae consortia and from <em>Chlorella sp.,</em> using urine as a culture medium, was analyzed in this study. These microorganisms require a supply of nutrients and light to stimulate their growth; and through variations of these factors, it is possible to improve lipid synthesis, fundamental elements for the production of value-added products. The BG11 culture medium was replaced with a urine-based medium (MOB) to cultivate a microalgae of the genus <em>Chlorella sp, </em>native to the State of Nuevo León. The growth of the microalgae in MOB was increased when compared to its growth in BG11. An improvement was also observed in the production of fatty acids and proteins, where the cultivation of <em>Chlorella sp</em>. with the urine medium (MOB) showed an average production (%) of 17.22% saturated fatty acids (SUFA's), 22.03% of monounsaturated fatty acids (MUFA's) and 60.73% of polyunsaturated fatty acids (PUFA's), demonstrated also in the high concentrations of mainly linoleic and linoleic fatty acids in the microalgae. This work, shows that human urine as a culture medium, provides enough nutrients to increase the production of biomass and oils; therefore, the use of this organic residue as a nutritive medium can be considered a suitable source for the production of essential fatty acids</p> J.C. Canino-Gómez B. Limón-Rodríguez P. Rivas-García C. Escamilla-Alvarado J.R. Morones-Ramírez M.M. Alcalá-Rodríguez ##submission.copyrightStatement## 2020-05-24 2020-05-24 19 Sup. 1 161 176 10.24275/rmiq/Bio1606 Dextran synthesis by native sugarcane microorganisms <p>The sugarcane agri-food industry boosts the Mexican economy in producing regions. Basing its relevance in sugar production yields. However, by-products are not widely exploited leaving an opportunity for diversification.&nbsp; In this study, three microorganism isolates (A, B, and C) were obtained from sugarcane kefir; the morphology of isolates B and C corresponded to the lactic acid bacterial genus Leuconostoc. Thus, we examined the potential for these isolates to produce EPSs, like dextran, a molecule with applications in pharmaceuticals, industrials, and foods. The experiment was performed adjusting the active culture concentration to 1 x 10<sup>6</sup> colony-forming units (CFU)/ml, the culture was maintained at 37°C in agitation at 150 rpm. The obtained EPSs were purified by ethanol and cold acetone precipitation. The results showed that B and C bacterial isolates had the capacity to produce EPSs (14 g/L for isolate B and 32 g/L for isolate C) after 24 h. Fourier-transform infrared spectroscopy (FT-IR) characterization indicated that the EPS was dextran. Further, the produced biopolymer had high solubility in water, avoided freezing at -4°C, and boiled at 85°C.</p> J.D. Castilla-Marroquín R. Hernández-Martínez H. Debernardi de la Vequia M.A. Ríos-Corripio J. Hernández-Rosas M. Rojas López F. Hernández-Rosas ##submission.copyrightStatement## 2020-06-29 2020-06-29 19 Sup. 1 177 185 10.24275/rmiq/Bio1793 Optimisation and dose responses of bioluminescent bacterial biosensors induced with target hydrocarbons <p>Routine analytical methods are constrained in the speed of application, sample throughput and inability to determine the right bioavailable loading of pollutants. Microbial biosensor technology resolved these constraints by offering the most rapid, sensitive, reliable and cost-effective technology, especially in a bioavailable context. This study describes the growth characterisation and optimisation of three different <em>lux</em>-marked biosensors and their induction bioassay, thus testing their responses to doses of target hydrocarbons (naphthalene, toluene, Isopropylbenzene) and solution of mixed hydrocarbons. These biosensors, <em>Pseudomonas fluorescence</em> HK44, <em>Escherichia coli</em> HMS174 and <em>Pseudomonas putida</em>TVA8 harbours <em>lux</em>CDABE reporter genes coupled to induction by hydrocarbons. Biosensors harvested at optimal exponential phase and induced with hydrocarbon using the optimised assay conditions are highly sensitive and responsive to their inducers in a proportionate dose-dependent status. The established dose responses of these catabolic biosensors signify the prospect of extrapolation for estimating the genuine contamination loading of pollutants for environmental relevance. However, several factors may contribute to the quenching effect at high concentration of inducers. Robust responsiveness to mixed hydrocarbon solution has been also realised accentuating its feasibility in analysing of real environmental samples containing heterogenous pollutants. This study emphasises the suitability of bioluminescent bacterial biosensors for pollutants analysis and notably the detection of soluble bioavailable fractions of diverse hydrocarbons, hence, serves as a reliable bioindicator of hydrocarbon pollution in an environment. Even so, the real value of biosensors is for a suite of ecologically justified biosensors to be applied in complementary combinations with other focused analytical or chemical methods for broad and resourceful inference.</p> H.I. Ibrahim M. Abdulrasheed A.F. Umar H. Lawal N. Ramírez S.A. Ahmad ##submission.copyrightStatement## 2020-04-19 2020-04-19 19 Sup. 1 187 199 10.24275/rmiq/Bio1274 A review of comparison study between Corona Viruses (SARS-CoV, MERS-CoV) and Novel Corona Virus (Covid-19) <p>Currently (March 2020) COVID-19 disease has recorded the most significant number of deaths and cases as compared to coronaviruses’ types. Initially, the virus was referred to as 2019-nCoV.&nbsp; Subsequently, the International Committee on Taxonomy of Viruses (ICTV) named it the SARS-CoV-2 virus because it is significantly similar to the causative agent of (SARS-CoVs). All Nidovirales’s viruses are positive-sense non-segmented and enveloped viruses. They have big genomes for the RNA viruses. The critical differences in the families of Nidovirus are noted in the type, sizes, and the number of structural proteins. The variances cause substantial alterations in the morphology and structure of the virions and nucleocapsids. Currently, the COVID- 19 diseases have recorded the most significant number of deaths and cases as compared to other kinds of coronaviruses. In conclusion, since the outbreak of (COVID-19) disease in China, the illness is spreading very quickly across the globe. There was no evidence showing that the viruses were manufactured in laboratories or engineered till now. Extensive lab work on the mechanisms of infection and genetic factors such as polymorphism that may play an essential role in disease is needed urgently.</p> W.S. Al-Qahtani L.M. Alneghery A.Q.S. Alqahtani M.D. ALKahtani S. Alkahtani ##submission.copyrightStatement## 2020-06-28 2020-06-28 19 Sup. 1 201 212 10.24275/rmiq/Bio1692 Biosynthesis of fibrinolytic agent urokinase by Enterococcus gallinarum isolated from sardine <p>Fibrinogen degradation by thrombin leads to the formation of fibrin clots in the blood which results in cardiovascular diseases due to which certain fibrinolytic agents are used to treat cardiovascular complications. Urokinase is being favored as a fibrinolytic agent due to its high fibrin specificity and fewer side effects. Therefore, the main objective of this research was the isolation of potent urokinase producing bacteria from soil, seawater, and fermented food samples. Thirty-five isolates that were capable of producing urokinase were isolated using sixty samples and subjected to secondary screening for urokinase estimation. Bacterial isolate QGA-20 that showed maximum enzyme activity 52.6±0.03 FU/ml/min was identified by 18s RNA sequencing as <em>Enterococcus gallinarum</em> which has never been reported before for urokinase production<em>. </em>Different physical and cultural parameters such as fermentation medium, incubation time, temperature, pH, carbon source, nitrogen source, inoculum size, and trace elements were optimized for submerged fermentation to synthesize urokinase. Maximum production of urokinase 81.3±0.02 FU/ml/min was obtained with M-5 fermentation media at 96 hrs of incubation, 37<sup>o</sup>C temperature, 7 pH, sucrose as carbon, and soya flour as a nitrogen source, 3% inoculum size and CaCl<sub>2</sub> as a trace element. In <em>in vitro </em>studies, urokinase enzyme was also applied for the disintegration of clot successfully. This study revealed a potent urokinase producer, reported first time, with appreciable clot lysis ability. &nbsp;&nbsp;</p> A. Nawaz S.Q. Gillani S.F. Tahir K.A. Shah S. Ashraf H. Mukhtar I.U. Haq ##submission.copyrightStatement## 2020-07-01 2020-07-01 19 Sup. 1 213 225 10.24275/rmiq/Bio1654 Biosynthesis, purification, kinetic and thermodynamic analysis of phytase from Aspergillus oryzae <p>Phytic acid is not digested by monogastric animals due to deficiency of an enzyme (Phytase) in their digestive tube. Due to this reason, poultry industry needs to add potent phytase in its feed for faster growth rates. Therefore, phytase producing fungal isolates (64) were isolated and subjected to submerged fermentation and maximum production (21.79± 0.05 U/mL/min) was obtained by fungal isolate UJIIB-29, which was identified as <em>Aspergillus oryzae </em>after18S rRNA sequencing. Under optimized conditions, best results were obtained using glucose phosphate broth as a medium after 7 days of incubation, at 30℃, pH 5.5 with 0.5% glucose and 0.3% ammonium sulfate as carbon and nitrogen sources, respectively when it was inoculated with 4% conidial suspension. Purification of phytase by anion exchange chromatography resulted in 89.8% yield, 1.93 folds purification and 53.5 U/mg specific activity. The molecular weight of purified phytase was determined as 53 kDa whereas, K<sub>m</sub> and V<sub>max</sub> were determined as 3.41 mM and 24.6±0.05 U/mL/min, respectively. Thermodynamic studies of the enzyme revealed activation energy (E<sub>a</sub>) and enthalpy of activation (ΔH) as 16.84 KJ/mol and 14.32 KJ/mol, respectively. Phytase showed enzyme activity up to 60℃ but at 30ºC and 5.5 pH, the enzyme showed maximum stablitity. The findings of the current study will help in developing an economical process for phytase biosynthesis. In addition, kinetic and thermodynamic studies will help in assessing applicability of phytase in harsh conditions.</p> I.U. Haq M.U. Javed A. Nawaz Y. Arshad H. Mukhtar ##submission.copyrightStatement## 2020-07-01 2020-07-01 19 Sup. 1 227 242 10.24275/rmiq/Bio1684 Bioremediation of heavy metals by melanised and non-melanised feathers and heavy metal resistant feather-degrading bacteria <p>Heavy metals are toxic and detrimental water pollutants. The continuous discharge of cadmium (Cd) and lead (Pb) containing effluents from industries within and around residential areas is worrisome since they do not only affects human beings, but also beneficial microbes, animals andvegetation due to their mobility in aqueous ecosystem, toxicity and non-biodegradability. The aim of this study is to compare the ability of black and white feathers to adsorb Cd and Pbin two aqueous media and to isolate Cd and Pb tolerant feather-degrading bacteria that will degrade the Cd and Pb polluted feather generated. Black and white chicken feathers were used as bio-adsorbent material in two Cd and Pb containing aqueous solutions (distilled water (DW)and feather meal broth(FMB)). The sorption capacity of the feathers was obtained by atomic absorption spectrometry andgravitational methods. Cd and Pb tolerant bacterium identified <em>Bacillus </em>sp. was isolated from the manure of local chick and used to degrade Cd and Pb polluted feathers. Result shows that black feathers possessed higher uptake capacity of Cd and Pb in FMB and DW, suggesting the high bio-absorption capacity of feathers in FMB that than in DW. A Cd and Pb resistant feather-degrading bacteria isolated from chicken manure were able to degrade about 40% Cd polluted feathers and 30% Pb polluted white feathers in 7 days. Even though the bacterium grew faster in FMB containing Cd polluted feathers, the degradation of Cd polluted white feathers was faster than black. Hydrolysates produced after complete degradation of polluted feathers contained low concentration of heavy metals. Bioremediation of heavy metals and recalcitrant chicken feather wastes can be achieved by melanised and un-melanised feathers and metal resistant feather-degrading bacteria.</p> Z.A. Abba S. Yahaya S.A. Ahmad N. Ramírez-Moreno I. Yusuf ##submission.copyrightStatement## 2020-06-28 2020-06-28 19 Sup. 1 243 252 10.24275/rmiq/Bio1551 Biosynthesis, optimization and characterization of ZnO nanoparticles using Bacillus cereus MN181367 and their antimicrobial activity against multidrug resistant bacteria <p>Zinc oxide nanoparticles ZnO NPs due to their unique properties have diverse applications in different fields of life. Bacterial synthesis of ZnO NPs is an eco-friendly, simple and inexpensive way. In this study, among eighteen bacterial isolates, eight confirmed ZnO NPs synthesis. On the basis of sharp absorption peak at 354 nm, growth conditions for gram positive <em>Bacillus cereus </em>H-SC1 were further optimized. Under different optimum parameters such as incubation temperature 37ºC, pH 9, inorganic salt (NH<sub>2</sub>)<sub>2</sub>SO<sub>4</sub>, SDS as surfactant, substrate (ZnSO<sub>4</sub>.7H<sub>2</sub>O) concentration 0.01 M and reaction time of two days under light condition, the ZnO NPs obtained had sharp peak at 352 nm and wide band gap of 3.5 eV. FTIR spectra indicated presence of amines and carbonyl groups as stabilizing agents. The scanning electron micrograph showed irregular shaped ZnO NPs and Zeta sizer indicated size ranging from 58.77-63.3 nm with PDI of 0.529. ZnO NPs exhibited negative zeta potential -7.39 mV. The antimicrobial assay by well diffusion method showed direct relationship of antibacterial activity with concentration of nanoparticles against <em>Escherichia coli, Staphylococcus aureus</em> and <em>Salmonella typhi</em>. Conclusively, bio-transformed ZnO NPs have great potential as an alternative to conventional antibiotics and as drug delivery tool.</p> M. Iqtedar H. Riaz A. Kaleem R. Abdullah A. Aihetasham S. Naz S. Sharif ##submission.copyrightStatement## 2020-06-29 2020-06-29 19 Sup. 1 253 266 10.24275/rmiq/Bio1605 Characterization of Geobacillus stearothermophilus protease for detergent industry <p>Cloning of protease gene from a thermophilic strain of <em>Geobacillus stearothermophilus </em>(B-1172) was carried out in <em>E. coli</em> BL 21, and its expression was studied. The expressed protease was purified followed by its identification. A 16.9 folds purification with 55.68% recovery of the protease was achieved by ammonium sulfate precipitation and gel filtration chromatography. The protease specific activity was 120 U mg<sup>−1</sup>. The purified enzyme remained stable at 90°C at a pH range 6-9. Its interaction with EDTA, different metal ions, inhibitors, surfactants and detergents was also mapped. Its interaction with EDTA showed no significant effect on the activity of the enzyme confirming its metaloprotease nature. Metal ions i.e. Ca<sup>2+</sup>, Mg<sup>2+</sup>, Ni<sup>2+</sup>, Cd<sup>2+</sup>, Cu<sup>2+</sup>, Zn<sup>2+</sup> showed no significant effect on the stability of protease. Its compatibility was checked with different commercial detergent (6 mg/mL) such as Surf Excel Arial, Bonus, wheel and Shine. It retained more than 80% proteolytic activity in all detergents after incubation at 50°C for 1 h. Wash performance analysis of the protease of <em>G. stearothermophilus </em>showed good results of de-staining of blood sample at various temperatures. Therefore, recombinant protease could prove as good candidate for commercial use in detergents.</p> I. Iqbal M.N. Aftab M.S. Afzal A. Kaleem ##submission.copyrightStatement## 2020-07-08 2020-07-08 19 Sup. 1 267 279 10.24275/rmiq/Bio1647 Electroanalytical study of infrageneric relationship of Lagerstroemia using glassy carbon electrode recorded voltammograms <p>An electrochemical fingerprint recording process has been developed for plant species identification and infrageneric relationship analysis. Electrochemical profiles of <em>Lagerstroemia </em><em>caudata, L. ambigua, L. speciosa, L. anhuiensis, L. balansae, L. minuticarpa, L. subcostata</em>, <em>L. indicas, L. fauriei, L. guilinensis, L. limii, Heimia myrtifolia </em>and <em>Lawsonia inermis</em> were recorded using leaf extract under three buffer solutions. The voltammetric data recorded under different buffer solutions can be derived as a scatter plot and a 2D density pattern for species recognition. As the distribution of electrochemical active compounds in plants is controlled by genes, these fingerprints can reflect differences at the genetic level between species. The dendrogram deduced from the electrochemical fingerprint has been used as evidence for infrageneric relationship investigation. The dendrogram deduced from electrochemical fingerprint indicates the <em>Heimia myrtifolia </em>and<em> Lawsonia inermis</em> were separated from other species, which is in a good agreement with their exotaxa position in this investigation. The intergeneric relationship deduced from data suggested the <em>L. speciosa</em> and<em> L. indicas</em> in a distant relationship.</p> X. Zhang R. Yang Z. Li M. Zhang Q. Wang Y. Xu L. Fu J. Du Y. Zheng J. Zhu Q. Liu ##submission.copyrightStatement## 2020-07-20 2020-07-20 19 Sup. 1 281 291 10.24275/rmiq/Bio1750 Purification, characterization, kinetics and thermodynamic analysis of polygalacturonase from Aspergillus tamarii for industrial applications <p>Increasing industrial demand has urged the scientists to biosynthesize polygalacturonase (PG) that would be operative, stable, cost effective and can be used in industrial applications particularly in fruit juice clarification and poultry feed. Polygalacturonase purification and characterization from <em>A. tamarii</em> was the main focus of the current research work. Fractionation by ammonium sulphate along with ion exchange chromatography was used for purification and 2.27 purification fold with 51.25 percentage yield was attained. SDS-PAGE analysis showed the molecular mass of purified enzyme as 70kDa. Enzyme kinetic assessment i.e. Km 2.85mg/mL and Vmax 55.55 in addition with thermodynamic determinants such as Ea=-39.84 KJ/mol, ΔH=37.62 KJ/mol and ΔS=-38.05 KJ/mol proves industrial stability of this enzyme. Further, different parameters were characterized which revealed that enzyme remained stable up to 50℃ and pH 8. Furthermore, PG found to retain its activity in the presence of different metals whereas some inhibitors reduced its activity i.e. PMSF and EDTA. The enzyme was found to have a better shelf life of 30 days at -20 and 4<sup>o</sup>C compared to room temperature. The reduction in turbidity of fresh juice and increase in body weight of chicks feeding on feed treated with purified PG proves its efficiency in industrial applications.</p> M. Munir R. Abdullah I.U. Haq A. Kaleem M. Iqtedar S. Ashraf ##submission.copyrightStatement## 2020-07-21 2020-07-21 19 Sup. 1 293 304 10.24275/rmiq/Bio1753 Comparative assessment of acids and alkali based pretreatment on sawdust for enhanced saccharification with thermophilic cellulases <p>The present study focuses on the use of thermophilic recombinant cellulases to produce fermentable sugars for conversion to bioethanol which is an important renewable energy resource to be worked upon due to climatic change, energy insecurity and nonrenewable nature of fossil fuels. Therefore, sawdust of pinus wood was subjected to pretreatment using different acids such as phosphoric, nitric, acetic and alkalis i.e. sodium hydroxide, calcium hydroxide and ammonia in various concentrations. Maximum delignification was observed using 8% nitric acid as it resulted in to 74.02% delignification and increased the cellulose availability to 81.8%. Subsequently, pretreated biomass was assessed for improvement in hydrolysis to less complex sugars employing thermophilic recombinant cellulases cloned from <em>Thermotoga petrophila</em>. Saccharification reaction parameters such as Incubation time, temperature, biomass and enzyme concentrations were optimized. The optimized conditions were revealed as 3 h incubation time, 65℃ temperature 0.1 % (w/v) substrate, 250, 2550 and 70140 U of Endo-1,4-β-glucanase, Exo-1,4-β-glucanase and β-1,4-Glucosidase, respectively. This optimization study resulted in 34.61% saccharification yield which is 1.82 folds increase compared to saccharification yield of untreated biomass. This study is unique in providing insight to pretreatment using Nitric acid as in literature use of nitric acid as a pretreatment agent is not well investigated.</p> I. Haq Z. Mustafa A. Nawaz H. Mukhtar X. Zhou Y. Xu ##submission.copyrightStatement## 2020-07-23 2020-07-23 19 Sup. 1 305 314 10.24275/rmiq/Bio1702 Physicochemical properties of biodegradable films of spine yam (Dioscorea rotundata), hydroxypropylmethylcellulose and clove oil (Syzygium aromaticum) <p>The development of biodegradable films using sustainable and renewable raw materials that produce materials with improved and active properties are a necessity for the current food packaging industry. Also, these materials must be low cost and friendly to the environment. The objective of this study was to evaluate the effect of the addition of clove essential oil on the mechanical, optical and barrier properties of yam starch and hydroxypropyl methylcellulose-based films. A decrease in water affinity and improved water vapour resistance was appreciated due to the addition of the essential oil. Furthermore, it was observed that as the concentration of HPMC increases, more resistant and deformable films are obtained. The films with the highest concentration of HPMC showed more resistant and deformable capacity, with stress strength of 20MPa and deformation capacity of 18% and the smallest elastic modulus with a value of 400Mpa. Besides, the films have a high barrier against UV light. The addition of clove essential oil and HPMC improved the physicochemical properties of yam starch-based films.</p> A. Villabona-Ortiz C. Tejada-Tovar R. Ortega-Toro ##submission.copyrightStatement## 2020-06-04 2020-06-04 19 Sup. 1 315 322 10.24275/rmiq/Alim1540 Bi-layer materials based on thermoplastic corn starch, polylactic acid and modified polypropylene <p>Currently, the development of environmentally friendly materials with suitable properties for industrial use has become of great importance. In this work, bilayer materials were developed by assembling thermoplastic- corn starch monolayers (TPS) combined with semi-crystalline polylactic acid (PLAs) monolayers and maleic anhydride grafted polypropylene (PP<sub>MA</sub>). The presence of a potassium sorbate solution was evaluated as interface material. Structural properties (FTIR and SEM), interactions with water (water vapor transmission rate, solubility in water and moisture content) and biodegradation of the materials were evaluated. The study showed that potassium sorbate promotes physical and chemical interactions between the monolayers studied. Furthermore, using a PLAs or PP<sub>MA</sub> monolayer greatly solves the water vapor permeability and sensitivity to liquid water that starch-based materials present. This result is interesting since the addition of an adhesive material to assemble the low chemical affinity monolayers would be avoided. The developed materials exhibit great potential for application as packaging in the food industry.</p> A. Diaz-Pedraza Y. Piñeros-Castro R. Ortega-Toro ##submission.copyrightStatement## 2020-06-16 2020-06-16 19 Sup. 1 323 331 10.24275/rmiq/Alim1655 Structural changes in the proteins from two species of the genus vigna by effect of different treatments <p>A study of the thermal treatment effect on the protein structure of the rice bean and cowpea bean was conduced. The protein was isolated by isoelectric focusing and electrophoretic pattern, FT-IR and FT-Raman spectroscopy were used for their characterization. The results showed that in both species the thermal treatment originate modifications on the conformational structure modifying the secondary structure, disorder level and agregation fractions. The FT-IR and FT-Raman spectros indicate that the main secondary structure is the protein of both species, was the β-sheet with a smaller contribution of the α-helix structure. The structure 3<sub>10</sub> helix and the sulfhydril groups were detected in the protein of both species, in addition the presence of some aminoacids also were observed (Cys, Lys, Trp, Phe, Tyr and Met). The electrophoretic pattern showed a significantl reduction in the number of high molecular weight subunits by effect of thermal treatment and isolation process, two hight molecular weight bands are mantained before and after treatments (23 kDa and 50 kDa), these fractions could be a stable subunits and common ancestor in both species.</p> L. González-Cruz J.M.S. Juárez-Goiz G. Teniente-Martínez G. Acosta-García N.L. Flores-Martínez A. Bernardino-Nicanor ##submission.copyrightStatement## 2020-06-29 2020-06-29 19 Sup. 1 333 347 10.24275/rmiq/Alim1550 Ionic gelation encapsulation of sesame oil with sodium alginate-nopal mucilage blends: Encapsulation efficiency and oxidative stability <p>Novel hydrogel beads were formed by ionic gelation between sodium alginate-nopal mucilage (SA-NM) for enhancing the encapsulation efficiency and oxidative stability of sesame oil (SO). SA-NM blends (2% w/v) were used 1:1 and 1:1.5 mass ratios. Ionic gelation was induced by dripping the SO-SA-NM homogenized dispersions with the help of a syringe into CaCl<sub>2 </sub>(2.5% w/v) solution with continuous stirring. The resulting beads were oven-dried and stored under controlled temperature conditions. The hydrogel beads were evaluated for size and shape, and for SO encapsulation efficiency, oxidative stability, and release kinetics. &nbsp;Results were compared with hydrogel beads made with only SA (2% w/v). The SA beads had a regular spherical shape with a mean size of ~2.19 mm, while the SA-NM hydrogels beads had an irregular semi-spherical shape with a significant smaller (~2.06-2.10 mm) size. SA-NM hydrogel beads displayed higher encapsulation efficiency (&gt; 75.44%) than SA beads (63.48%), and provided better protection to SO against oxidation during storage than the SA beads and free SO oil. Oxidation kinetics were of zero-order in all cases. The release kinetics of SO was diffusion controlled and was significantly slower for SA-NM than for SA beads. Our results indicate that SA-NM mixtures may be considered as novel potential additives for food industry applications.</p> S.K. Velázquez-Gutiérrez E. Alpizar-Reyes J. Cruz-Olivares J.F. Barrera-Pichardo M.E. Rodríguez-Huezo C. Pérez-Alonso ##submission.copyrightStatement## 2020-06-28 2020-06-28 19 Sup. 1 349 362 10.24275/rmiq/Alim1642 pH-indicating properties and storage stability of a smart edible film based on nopal-mucilage/gellan gum and red cabbage anthocyanins <p><em>Nopal mucilage is a complex polysaccharide with great potential in the preparation of the films to food packaging. In this work, was develop a smart edible film with pH-indicating capabilities based on nopal mucilage, gellan gum, and red cabbage anthocyanins (70:20 w/w, and 10% respectively). Physical properties, appearance, and colorimetric functionality were characterized to pH range 2.5-5.9. Color stability, measured by CIELAB, was tested with different storage conditions and time and interpreted by differential tristimulus colorimetry. Results showed films whit uniform appearance, flexibility, easy-handling, and excellent color response within the pH range studied. The evolution of color difference (</em><em>ΔE*ab) confirmed that the colorimetric functionality of films was stable at short storage periods (8 days) under natural conditions of sunlight and oxygen exposure, while a more extended storage period was affected. Results showed that the film is an excellent barrier and presents color changes triggered by pH changes.</em></p> L.G. Solano-Doblado F.J. Heredia B. Gordillo-Arrobas G. Davila-Ortiz L. Alamilla-Beltran A. Maciel-Cerda C. Jiménez-Martínez ##submission.copyrightStatement## 2020-07-01 2020-07-01 19 Sup. 1 363 374 10.24275/rmiq/Alim1583 Chitosan enhances the production of antioxidant phenolic compounds in carrot through a synergistic effect with wounding stress <p>In the present study, the postharvest application of wounding stress applied alone and combined with chitosan was evaluated as an innovative tool to increase the concentration of antioxidant phenolic compounds in carrots. Carrots were wounded to obtain pie-cuts and shreds. The whole and wounded tissue (300 g) was sprayed with a chitosan suspension (0.5% w/v), and the content of individual phenolics were evaluated before and after 48 h of storage at 20 °C. When the two stresses were combined (wounding+chitosan) a synergistic effect on the accumulation of phenolic compounds were obtained. For instance, after storage chlorogenic acid and <em>p</em>-coumaric acid derivative increased by 5,069.1% and 385%, respectively, in chitosan treated carrot shreds. Similarly, isocoumarin, which was not detected in carrots before storage, showed a high accumulation after storage in chitosan treated carrot shreds (1,074.8 mg/kg). Results presented herein demonstrated that the combination of wounding stress and chitosan can be used as an effective strategy to increase the content of antioxidant phenolic compounds in carrots. The stressed carrot tissue can be used as raw material to obtain value-added food products or for the extraction and purification of phenolics with application in the food and dietary supplement industries.</p> L. Berumen-Guerrero E. Ortega-Hernández A. Gastélum-Estrada A. Hurtado-Romero D. Navarro-López J. Benavides D.A. Jacobo-Velázquez ##submission.copyrightStatement## 2020-07-02 2020-07-02 19 Sup. 1 375 384 10.24275/rmiq/Alim1764 Effect of different extraction methods on cottonseed oil yield <p>Cotton (<em>Gossypium hirsutum</em> L.) is an important fibre crop of global significance. It is mainly utilised for the textile industry, and its seeds as cattle feed and to re-harvest fields. However, an important amount of the cottonseed obtained during processing is discarded. Some reports indicate that cottonseed contains high-quality protein and important lipid content. The aim of the present study was to compare different extraction methods (Soxhlet, mechanical and ultrasound-assisted) in order to achieve the highest extraction yield of cottonseed oil (CSO). The extraction efficiency was measured based on the effects of temperature, organic solvent (OS), extraction time and solvent:seed (s:s) ratio, using a Box-Behnken 3<sup>4</sup> experimental design. From our results, ultrasound-assisted extraction had the highest extraction yield (38.25%) at 45 <sup>o</sup>C, after 1 h for a 10:1 ratio using Folch mixture as OS. Palmitic, oleic and linoleic acids were the main residues in the characterised CSO, and this oil can be utilized for biodiesel production. This research intends to promote the use of this agroindustrial by-product to add value to cottonseed.</p> E. Rojo-Gutiérrez J.J. Buenrostro-Figueroa R. Natividad-Rangel R. Romero-Romero D.R. Sepulveda R. Baeza-Jimenez ##submission.copyrightStatement## 2020-07-19 2020-07-19 19 Sup. 1 385 394 10.24275/rmiq/Alim1704 Extrusion parameters to produce a PLA-starch derived thermoplastic polymer <p>The purpose of this study was to develop a biodegradable thermoplastic polymer based on starch and polylactic acid (PLA) blends with mechanical properties adequate for a wide range of applications. A thermoplastic starch (TPS) was formulated using native corn starch, glycerol as a plasticizer ranging from 30 to 50% (w/w) and citric acid (1.0%, w/w) as a crosslinker. The TPS was mixed with polylactic acid (PLA) [0-50%, w/w]. The material was prepared by extrusion using a single screw extruder. The variables for the experiment design were PLA concentration, extrusion temperature, glycerol concentration, and velocity of the screw. Samples before and after extrusion were characterized by Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DCS), Fourier Transform Infrared Spectroscopy (FTIR) and X-Ray Diffraction. We evaluated the mechanical Young’s modulus, tensile strength, and elongation at break. All treatments were performed according to the experiment design. The results of the characterization of the material were analyzed using the response surface methodology (RSM). The RSM revealed the optimum PLA concentration, extrusion temperature, and screw velocity that would produce a corn starch-PLA biodegradable plastic with mechanical properties closer to those of the petroleum-derived plastics.</p> H.I. García-Cruz M.R. Jaime-Fonseca E. Von Borries-Medrano H. Vieyra ##submission.copyrightStatement## 2020-07-04 2020-07-04 19 Sup. 1 395 412 10.24275/rmiq/Poly1529 Degradation study of copolymers of PLLGA to be used as potential polymeric matrix in coronary stents <p>In this work, three types of poli(L-lactic-co-glycolic acid) copolymers (PLLGA) with different lactide to glycolide ratio (70:30, 80:20 and 90:10 %wt.<sub>L-LA</sub>:%wt.<sub>GA</sub>) were synthesized. The materials were characterized by known techniques. The degradation study of PLLGA was made in saline solution and followed by molecular weight change and mass loss percentage. The results showed that PLLGA degradation followed a first order kinetic. Prednisone (immunosuppressive drug) was incorporated into polymeric matrix. The release process was quantified by drug concentration change in the saline solution using UV spectroscopy at 240nm. In this way, diffusion coefficients of prednisone into copolymers were calculated. The results showed that prednisone released was governed by two phenomena: diffusion and degradation. The drug released kinetic was adjusted at two models proposed for biodegradable systems: the model of Higuchi and the model of Charlier. Drug diffusion coefficients were higher in the copolymers with higher percentage of glycolic acid, and they were increasing as the degradation process was progressing. The cytotoxicity assay evidenced that PLLGA copolymers and PLLGA degradation products were not toxic in endothelial cells. Finally, a 3D printer was built and programmed to explore the stent fabrication to be used as potential polymeric matrix in coronary stents.</p> M.J. Valarezo-Ulloa J.I. Chairez-Oria G. Martínez-Mejía B.E. García-Pérez J.M. del Río C. Gómez-Yañez M. Corea ##submission.copyrightStatement## 2020-06-16 2020-06-16 19 Sup. 1 413 427 10.24275/rmiq/Poly1508 Sulfonated rim rubber used as a solid catalyst for the biodiesel production with oleic acid and optimized by Box-Behnken method <p>Esterification of oleic acid was carried out to obtain methyl esters at temperatures below the critical point of methanol in the presence of sulfonated carbon. That was obtained by pyrolysis from tire rubber and use as catalytic support after sulfonated. The sulfonated carbonaceous material in the laboratory was analyzed by spectroscopy and microscopic techniques: IR spectroscopy, X-ray diffractometry, programmed desorption at a temperature (TG-DTG), X-ray photoelectron spectroscopy and scanning electron microscopy. The physicochemical properties of catalyst favor high performance in the production of biodiesel from oleic acid, are easily separated from the liquid mixture at the end of the reaction. At the temperature of 200 °C, with a reaction time of 20 min and a catalyst amount of 0.03% by weight, was the optimal experimental conditions for the esterification of oleic acid with methanol, giving a conversion of 97.9% of free fatty acids according to the response surface method. The Box-Behnken experiments were applied in order to evaluate the effects of the production parameters of biodiesel and find out the optimal conditions to obtain the maximum yield. Interestingly, stable catalytic activity in several reaction cycles was found.</p> L.A. Sánchez-Olmos M. Sánchez-Cárdenas K. Sathish-Kumar D.N. Tirado-González F.J. Rodríguez-Valadez ##submission.copyrightStatement## 2020-07-01 2020-07-01 19 Sup. 1 429 444 10.24275/rmiq/Cat1625 Determination of kinetic parameters of nucleation and growth of acetylsalicylic acid crystals in ethanol <p>In this work, nucleation and growth kinetics parameters for the acetylsalicylic acid (ASA) -ethanol system were determined from experimental data obtained in a batch crystallization process at different operating conditions. Saturated solutions, between 293.15 K and 313.15 K, were prepared and cooled following linear profiles in the range of 5 to 15 K/h. Measurements online of temperature, density and crystal size distribution were registered every 30 seconds. In addition, an algorithm was developed in Matlab to solve the mathematical model of the crystallization process. The model included the population and mass balances and power-law equations for nucleation and growth. The algorithm allowed optimizing the kinetic parameters by minimizing the sum of the square of the difference between the experimental and calculated profiles for the concentration of ASA in solution. The results showed that increasing the cooling rate increased the growth rates but decreased the nucleation rates. Besides, the average value of <em>g</em> supported that diffusional effects dominate crystal growth and the value of <em>b</em> suggested that secondary nucleation promoted the creation of new nuclei. The global error in the estimation of the kinetic parameters was less than 3%.</p> X.M. Medina-Galván P.A. Quintana-Hernández J.N. Reyes-Valadez L.F. Fuentes-Cortés ##submission.copyrightStatement## 2020-07-18 2020-07-18 19 Sup. 1 445 456 10.24275/rmiq/Cat1574 Effect of cold air plasmas on the morphology and thermal stability of bleached hemp fibers <p>The use of cold plasma surface modification techniques has lately gained increasing interest as a complementary green option to modify the thermal stability of bio-based fibers, and thus make them more suitable for polymer reinforcing applications. In this study, commercial bleached hemp (CBH) fibers were modified using low-pressure rotatory plasma (LPRP) and atmospheric-pressure plasma jet (APPJ) devices to be further characterized by Fourier transform infrared spectroscopy―attenuated total reflectance mode (FTIR-ATR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). FTIR analysis evidenced the oxidation and crosslinking of cellulose chains. XRD analysis revealed a slight increase in interplanar distances of cellulose chains, that was attributed to the interchain insertion of functional groups. SEM images displayed much rougher surfaces for the treated CBH fibers than for the untreated one. TGA showed that LPRP (30 min treatment) and APPJ increased the thermal resistance of CBH fibers in 30 and 61 °C, respectively. For LPRP, a longer exposition time (180 min) provoked significant eroding without improving the thermal resistance. Finally, the cold plasma surface modification of bleached hemp fibers may well assist with the mechanical interlocking and thermal resistance (during processing) when applied in polymer reinforcing.</p> F.J. Alonso-Montemayor C.M. López-Badillo C.N. Aguilar-González F. Ávalos-Belmontes A.O. Castañeda-Facio R. Reyna-Martínez M.G. Neira-Velázquez G. Soria-Argüello D. Navarro-Rodríguez M. Delgado-Aguilar R.I. Narro-Céspedes ##submission.copyrightStatement## 2020-06-04 2020-06-04 19 Sup. 1 457 467 10.24275/rmiq/Mat1510 Corrosion behavior of steel reinforcement bars embedded in concrete with sugar cane bagasse ash <p>The corrosion behaviour of G42 steel reinforcing bars embedded in modified concrete was studied, using cylindrical concrete specimens with sugar cane bagasse ash (SCBA) as partial replacement for Portland cement at proportions of 0, 15, 30 and 45 wt%. The specimens were exposed to a brine environment using the impressed current technique during 0, 8, 16, 32 and 64 h, in order to accelerate the corrosion. Behaviour of the corrosion process was evaluated by means of electrochemical measurements using the Electrochemical Impedance Spectroscopy technique (EIS). The results showed an impedance reduction in concrete after impressed current exposure in all tested formulations. Lower reaction rates were observed in specimens with 0 and 15 wt% of SCBA content after 64 hours of accelerated corrosion. The impedance spectra of the samples with 45 wt% of SCBA content were compared with an equivalent circuit model, where high corrosion damage was observed.</p> D.E. Ramírez-Arreola F.J. Aranda-García C. Sedano de la Rosa A.M. Camacho-Vidrio R.V. Silva ##submission.copyrightStatement## 2020-06-29 2020-06-29 19 Sup. 1 469 481 10.24275/rmiq/Mat1651 Oxygen transfer in a three-phase bubble column using solid polymers as mass transfer vectors <p>Three solid polymers; Kraton, Elvax, and Desmopan, previously suggested to be used in three-phase reactors, were evaluated for their ability to enhance oxygen transfer in a bubble column. These vectors were first characterized through determination of particle size distribution, surface roughness, specific surface area, density, void fraction and thermal stability. Oxygen transfer was then determined with a non-coalescing medium using polymer volume fractions from 0 to 75% in a 4 L bubble column operated at air flow rates ranging from 1 to 6 L/min. The results showed that the oxygen transfer was significantly improved in presence of 10 and 25% of Kraton and Elvax, compared with control experiment with no polymer. A maximum oxygen transfer improvement of 90%, compared with control, was observed with 10% Kraton. With Desmopan, no positive effect on oxygen transfer was observed regardless of the vector percentage used. Phase’s dispersion and oxygen transfer was further explored in presence of 10% Kraton. Gas holdup, Sauter mean bubble diameter and vector dispersion were characterized by means of high speed digital image analysis. The results showed that the enhancement of oxygen transfer mediated by Kraton was mainly caused by an increase of gas holdup and consequently of the gas/liquid surface area.</p> G. Quijano M. Franco-Morgado M.S. Córdova-Aguilar E. Galindo F. Thalasso ##submission.copyrightStatement## 2020-06-07 2020-06-07 19 Sup. 1 483 494 10.24275/rmiq/Proc1486 Average velocity profile between a fluid layer and a porous medium: Brinkman boundary layer <pre>It has been mentioned that, the existence of some terms in Darcy's law are the result of the up-scaling method applied to the Stokes flow problem at the pore scale. To address this debate, in this work we perform, at the pore-scale, flow simulations in a free fluid/porous medium system using different models of granular porous media. The local velocity obtained from the Stokes equation allows to obtain the Darcy-scale velocity profiles by a direct averaging instead of using the up-scaled model. The results show the existence of a smooth transition zone in the average velocity profiles near the free fluid/porous medium inter-region. The size and shape of such transition zone depend on the size of the averaging domain and they are a result of averaging local quantities and not a result of solving average equations. In this way, we confirm the existence of an average velocity boundary layer (<em>i.e.</em> Brinkman boundary layer); thus the pertinence of considering other terms in Darcy's law can be certainly justified. We have also determined the extension of the influence of the flow in the free fluid inside the porous medium and the perturbation of the flow in porous medium on the flow in the free fluid.</pre> R. Hernandez-Rodriguez B. Goyeau P. Angot J.A. Ochoa-Tapia ##submission.copyrightStatement## 2020-04-29 2020-04-29 19 Sup. 1 495 520 10.24275/rmiq/Fen843