Revista Mexicana de Ingeniería Química

Functional properties and antioxidant activity of protein fractions of spirulina (Arthrospira maxima)

K. Peña-Solis — 2022-12-10

In this research, spirulina of the species Arthrospira maxima, produced and donated by the company "NanoMex Espirulina" located in the city of Tlaxcala, Tlax., Mexico, was used. The proximal chemical composition of spirulina was determined. A sequential protein extraction was performed from frozen and macerated spirulina, initially a 0.9% (w/v) suspension of spirulina in dry weight was prepared in distilled water, subsequently, the residue was solubilized in saline solution (0.4 mM Na₂SO₄), then the residue was solubilized in water at pH 11 and finally the residue was solubilized in 70% ethanol; at each stage the solubilized protein was precipitated with 5% trichloroacetic acid and recovered by centrifugation. The fractions of albumins, globulins and glutelins were obtained, the prolamins were not. The antioxidant activity, the functional properties and the electrophoretic profile of the protein fractions obtained were determined. The albumin fraction presented the highest yield, so they are the ones with potential use in the food industry. Most of the proteins in spirulina are soluble in water and are of low molecular weight.

Optimization of Pleurotus eryngii culture parameters and development of improved strains by mating of compatible neohaplonts

C. Alpuche-González — 2022-12-10

Production parameters for cultivation of P. eryngii were established. With 21 days incubation, a substrate of wheat straw (45%), sawdust (20%), wheat bran (16%) and gluten (5%) packed in 3.5 kg bags produced higher BE (103%) than a cotton waste substrate (BE=74%). Cold treatment or scratching of substrate for induction of fruiting resulted unnecessary. Strains FQ and MB of P. eryngii were dedikaryotized by blending mycelium suspensions for 300 seconds and inoculation 50 µL of homogenate into solutions with 20 g/L glucose and peptone. In two dedikaryotization experiments, both component monokaryons (neohaplonts) were recovered from strains FQ and MB. Hybrids and reconstructed parental dikaryons were obtained by mating neohaplonts. The strains generated in the first dedikaryotization experiment were fruited. The parental strains produced lower BE (103, 84%) than reconstructed strains (183, 101%) and two hybrids (106, 174%). After a second dedikaryotization, 17 neohaplonts were mated to produce 3 reconstructed strains and 7 hybrids. Their growth curves were determined on 2 solid media (MEA agar and wheat). The Baranyi model showed the best adjustment to growth curves and allowed to separate them into statistically different groups and to calculate the corresponding kinetic parameters (μ_max, λ) on MEA agar and wheat.

Biodegradation of crude oil present in wastewaters: evaluation of biosurfactant production and catechol 2,3 dioxygenase activity

M. Canul-Chan — 2023-01-06

Water demand is increasing because of demographic and urban development in the last decades. Crude oil is an essential energy resource for many anthropogenic activities. However, it is associated with the generation of environmental pollution. In the present work, a native microbial consortium was used to study hydrocarbon biodegradation of crude oil and its potential use to remove organic pollutants in wastewater. The kinetic degradation of crude oil was analyzed to determine the production of biosurfactants and the enzyme activity of catechol 2,3 dioxygenase. The degradation of the hydrocarbon was determined by aromatic-hydrocarbons (96.11%) and total-hydrocarbons (74.23%). The maximum values of the biosurfactant production were evaluated by oil displacement (206.95 mg/L) and emulsification capacity (DO600 0.2895). The kinetic analysis showed that the complex mixture of hydrocarbons was the main responsible for generating the stress to synthesize biosurfactants through a native microbial consortium. However, the decrease in catechol 2,3 dioxygenase activity and biosurfactant production was related to the degradation of aromatic hydrocarbons. The microbial consortium was capable to produce biosurfactants during crude oil degradation, and it has a great potential to remove aromatic hydrocarbons present in wastewater.

Biodegradation of polystyrene with laccase-producing enterobacteria isolated from a municipal waste dump

C. Jiménez-Perez — 2023-01-10

In this work, the ability to biodegrade two samples of polystyrene (PS) was evaluated: crystal and expanded with three bacterial strains isolated from PS waste collected in the municipal dump of Chimalhuacán, Estado de Mexico. The biodegradation potential of the isolated strains was determined by means of substrate weight loss assays. All three bacterial strains were found to be able to biodegrade both types of PS. The study also aimed to determine if the isolated bacteria produce laccase. This enzyme belongs to the oxidoreductase family and is known to degrade polyethylene. Copper sulfate (CuSO₄) was used as the inducer of laccase activity, and an increase in enzyme activity was observed with simultaneous loss of PS weight compared to the control assay without CuSO₄. It was concluded that laccase directly participated in the biodegradation of this synthetic polymer. Enterobacter sp. UAMI-C3 proved to be the most efficient strain in the degradation of expanded PS with a weight decrease of 0.85% in 30 days with laccase activity at 9.8 x 10^-3 U/mL.

Ethanol production from Mexican fruit wastes using a new Saccharomyces cerevisiae strain

L.C. Antonio-Narcizo — 2023-01-18

In the Mexican croplands are generated large amounts of agroindustrial wastes that are usually not exploited. Damaged fruits wasted in the municipality of Tres Valles, Veracruz, are an excellent feedstock to produce ethanol, since do not need a sophisticated pretreatment and have high fermentable sugar concentrations. In this work is described ethanol production from damaged fruits by a new strain of Saccharomyces cerevisiae isolated from agave sp. wastes. Fermentations were carried out in batch and repeated batch cultures using biocatalysts formed by S. cerevisiae AP1 cells immobilized into alginate-coated polyester fiberfill. Biocatalysts showed a high fermentative capability at reducing sugar concentrations higher than 30 g L^-1. In batch cultures, with 32.58 g reducing sugar L^-1, was produced up to 15.39 g ethanol L^-1 at 16 h, with a volumetric productivity of 0.962 g L^-1 h^-1 and a fermentation efficiency of 94.77%. Instead in a 5-cycle repeated batch fermentation, with a reducing sugar content among 30 to 43 g L^-1, ethanol production in each cycle was fast, higher than 15 g L^-1, with fermentation efficiencies higher than 80%, and with volumetric productivities from 2.5 to 2.9 g L^-1 h^-1 after second cycle. Afterwards five cycles of repeated batch fermentation, total ethanol production was 95.41 g L^-1 in just 44 h process.

Respiro-fermentative metabolism in yeast cultivated in solid-state culture: The Crabtree effect and ethanol production

R.J. Estrada-Martinez — 2023-03-13

A strong inoculum in solid-state culture (SSC) is achieved by using a high-density, high-activity microbial population. To determine the best conditions for yeast propagation, the Crabtree effect was analyzed. Inoculum production was carried out in Erlenmeyer flasks with different designs (baffled, coiled and conventional) and filling volumes (20 and 40 %). A 20% filling volume resulted in better air diffusion, leading to improved yeast growth independently of the flask configuration. Yeasts have adapted to produce ethanol under aerobic conditions to compete with other microorganisms. With commercial baker's yeast, the highest ethanol production was achieved at the laboratory scale (195.70±17.25 g ethanol/kg dry matter [DM]). There was no difference in ethanol production between the tubular reactor (171.10±10.87 g ethanol/kg DM) and in the pilot batch bioreactor (165.03±9.90 g ethanol/kg DM) using S. cerevisiae yeast ITD00196 as inoculum. Crabtree-positive yeasts have potential for rapid ethanol production in organic waste fermentation without thermochemical or enzymatic pre-treatment by SSC in the laboratory and at pilot-scale.

Integration of extraction and acid hydrolysis processes as a strategy for better use and obtaining products from coffee residues

E.L. Hernández-Teyssier — 2023-03-15

The present study used a mixture of coffee processing residues to develop integrated processing for extracting high-value compounds with solvents and acid hydrolysis. The waste mixture comprised 55% bagasse, 40% husk, and 5% parchment. The physicochemical characterization showed 9.39 ± 0.37% of soluble fraction, and 90.61 ± 0.37% of the insoluble fraction, of which 60.41 ± 0.67% was cellulose, 6.44 ± 1.32% was hemicellulose and 23.21 ± 0.29% was lignin. In the first stage, the treatments of Organosolv and Organosolv assisted with ultrasonic (OAU) were applied at three particle sizes. The maximum yields of polyphenols were obtained with the smallest particle size and were 11.32 ± 0.63 mg GAE (gallic acid equivalents)/g DW (dry weight) for Organosolv and 10.12 ± 0.55 mg GAE/g DW for OAU. The best results for carbohydrate release were obtained with acid hydrolysis (0.5 % H₂SO₄) and OAU pretreatment. Principal component analysis indicated that the OAU treatment with hydrolysis at 15 psi was the best to obtain polyphenols, arabinose, and xylose.

Conventional and non-conventional extraction of functional compounds from jiotilla (Escontria chiotilla) fruits and evaluation of their antioxidant activity

D.C. Franco-Vásquez — 2022-12-09

There is a growing interest in obtaining bioactive compounds from underexplored plant organisms such as jiotilla (Escontria chiotilla), a species of the Cactaceae family whose fruit is a source of betalains and phenolic compounds. Therefore, it is relevant to establish an extraction methodology that allows a higher yield of bioactive compounds and greater functional activity to be obtained. In this study, the conventional extraction process was optimized to obtain betalains, phenolic compounds, and antioxidant activity from jiotilla extracts and results were compared with those obtained by ultrasound-assisted and ultrasound-microwave extraction. Optimum conditions for conventional extraction of betalains (90.56 ± 0.88 mg/100 g fresh weight (g_fw)) and phenolic compounds (129.12 ± 14.21 mg/100 g_fw) were 37.5% v/v ethanol, an m : v ratio of 1 : 20, and 40 min maceration with shaking. Ultrasound-assisted extraction increased the phenolic compound content of the extract by 34.01% and its antioxidant activity by 25.68%, a positive correlation being found between these parameters. Ultrasound-microwave extraction did not improve extraction yields compared to the other two technologies. These results show that the extraction method affects the content of functional compounds and antioxidant activity and pinpoint that jiotilla fruits can be a viable alternative for extraction of betalains and phenolic compounds.

Influence of power density and geometry of young cactus cladodes (Opuntia ficus-indica (L.) Mill.) on intermittent microwave drying kinetics

T. Espinosa-Solares — 2022-12-18

Due to its multiple uses, the production and consumption of nopal has increased worldwide in recent years. The influence of power density (60.3 to 538.9 W g_db^-1) on the intermittent microwave drying of young cladodes, of different sizes, was studied. In general, all drying treatments showed a sigmoid shape and three drying periods: heating (I), constant rate (II) and falling rate (III). Empirical models were used to model drying kinetics. However, although they had a good fit (R² from 0.965-0.998) they do not exactly represent the changes between drying periods. According to the structural evidence, water migrates from the inside of the cladode to the surface by the sides, where there is no cuticle (removed by the thorn quitting process). It was determined that the drying rate in period II depends exclusively on the power density applied and not on the cladode’s geometry. However, in period III the data obtained of effective diffusivity (D_eff, 2.20x10^-6 to 5.59x10^-5m² s^-1) showed that drying rate is affected by the size and thickness of cladodes.

Effect of sodium alginate-calcium chloride coating and glycerol and sorbitol concentration on oxidative stability and fungal growth of Persian walnut (Juglans regia L.)

P. Sharafi-Badr — 2023-01-06

The effect of extracted sodium alginate (SA) (0.25, 0.50, 0.75, and 1.00% w/w) from Sargassum angustifolium along with sorbitol (S), glycerol (G), and before and after calcium chloride (CaCl₂) treatment as a coating material were evaluated on oxidative stability, fungal growth, and sensorial properties of Persian walnut Juglans regia. In the second month of the storage period, peroxide and acid values of alginate-Ca²⁺coated walnuts decreased compared to the uncoated sample. Moisture loss was reduced, and the color parameter values were significantly higher in these samples than in uncoated ones. The fungal growth rate decreased by about 1.5-5.0 Log CFU/g in coated walnuts at the nin^th week of the storage. SA was an excellent protective barrier to water vapor and oxygen permeability to preserve walnuts against oxidative stress and fungal growth. In addition, SA as a coating material increased oxidative stability and decreased fungal spoilage of walnuts without any adverse changes in their color or sensorial acceptability.

Economic evaluation of protein recovery process from Argentinian soybean extruded-expelled meals

C. Accoroni — 2023-01-31

Soybean extruded-expelled (EE) meals are the byproduct of the soybean oil extraction process commonly used by small and medium- sized Argentinean companies. In this study, the economic feasibility of protein concentrate production from soybean EE meals was evaluated. A processing daily capacity of 18 ton of EE meals was considered, resulting in an annual production of 1,500 ton of protein concentrate. The proposed methodology considered a pH change process consisting of 3 cycles of alkaline extraction at 60 ºC followed by isoelectric precipitation at low temperature using hydrochloric acid, which resulted in a final product with a protein content of 75 % (db) and a productivity of 0.28 kg product/kg soybean EE meals. To analyze a practical case, proposed production was carried out as an extension of a typical medium-sized soybean extrusion- expelling plant. As a result, the necessary capital investment was estimated to be US$2.7 million. Additional financial performance indicators were computed, including net present value and internal rate of return, and it was concluded that the proposal to obtain a protein concentrate from soybean EE meals was economically viable on an industrial scale if sale prices are above 2,267 US$/ton.

Rheological and structural properties of complex coacervates of Amaranthus hypochondriacus protein-citrus pectin

L. Hernández-Rodriguez — 2023-02-01

Complex coacervates were formed by electrostatic interaction between amaranth protein isolated (API) and citrus pectin (CP), at different API:CP weight ratio (3:1, 5:1, and 7: 1) and pH values (3.5 and 4.5). The physicochemical, rheological, and microstructural properties of the coacervates were investigated. The FTIR spectrum of the coacervates showed changes in the peaks at 1636 and 1153 cm^-1 compared to the spectrum of API and CP, confirming the formation of the complex coacervates. A fine, structured, and compact structure was observed in the coacervates formed at pH 3.5; in contrast, a matrix composed of relatively large aggregates was observed for the coacervates formed at pH 4.5. Particle size of the coacervates increased as the API:CP weight ratio and pH increased, ranging the hydrodynamic diameter (Dh) from 1043 ± 39 to 2670 ± 30 nm. The apparent viscosity of the coacervates increased as the API:CP weight ratio increased and pH decreased. All the variations of complex coacervates presented G' values (storage modulus) higher than the G'' values (loss modulus), indicating a predominantly elastic rheological behavior. The knowledge generated could contribute to the application of the studied complex coacervates in the food industry.

Evaluation of physicochemical, rheological, textural and thermal properties of Mexican manchego-type cheese manufactured from goat´s milk

A.M. Ortíz-Deleón — 2023-03-02

Cheeses made from goat’s milk have gained importance in some regions of Mexico, where their diversification of their use beyond traditional sweets has attracted the attention of scientists and food technologists. In this work, Mexican manchego-type cheeses made with goat´s milk (GC) at different stages of maturation (60 and 90 days) were subjected to physicochemical, texture (TPA), microstructure, rheological, and thermal characterization analysis. Comparisons with cheeses made with cow´s milk (CC, 60 and 90 days) were done. In general, GC showed lower texture values and viscoelastic properties, with higher melting capacity and lower resistance to deformation because of heat treatment, with respect to CC. In addition, differences were observed in the microstructure, texture, and thermal properties with respect to the maturation time and the type of milk used. The characteristics of the cheeses were influenced by the moisture content and the maturation time in the samples, thus decreasing the texture properties and thermal stability, as the moisture decreased and the maturation time increased. After analyzing the cheeses in the maturation time, valuable information can be obtained for the agroindustry, after defining what is the appropriate maturation time for the manchego-type cheese, made with goat's milk, to produce a structure that exhibits the rheological properties, texture and melting of greater acceptance by the consumer, for use in Mexican gastronomy.

Assessment of moisture adsorption and desorption isotherms, hysteresis phenomenon and thermodynamic analysis of habanero chili (Capsicum chinense) powder

M. Luna-Flores — 2023-03-18

Moisture adsorption and desorption isotherms (MSIs) of habanero chili powder were determined at different temperatures (20-55 °C) and water activities (a_w; 0.10-0.90) using the Dynamic Vapor Sorption (DVS) method and applying the conditions typically used during the storage, packaging, and drying of habanero chili. The MSIs were sigmoidal (Type II); the best fit models were GAB and Peleg. The sorption capacity of habanero chili powder decreased with increasing temperature and constant a_w, becoming less hygroscopic. The hysteresis phenomenon was observed for all the temperatures evaluated. Thermodynamic properties were strongly dependent on the equilibrium moisture content (EMC). The net and total isosteric heat were higher for desorption than for adsorption, in both, they decreased as EMC increased. Sorption entropy and Gibbs free energy also decreased with rising EMC. Furthermore, the sorption surface area (SSA) decreased with increasing temperature. This information is essential to know the optimal storage and processing conditions to preserve the quality and prolong the shelf life of habanero chili powder.

Kinetic evaluation of photocatalytic decoloration of Synozol Red K3BS dye using TiO2-anatase and direct solar radiation

S.A. Ramírez-Revilla — 2023-01-18

The intense solar radiation of the city of Arequipa has been used as an activation factor for TiO₂ anatase to evaluate the decoloration kinetics of the Synozol Red K3BS textile dye. For this purpose, a factorial design (2³) was developed to optimize the values of reaction time, pH and TiO₂ doses for 200 mL of solution. The optimal factors for the study were: a 60 min duration, a pH of 3 and 0.1 g of photocatalyst. The first-order kinetic model adequately explained the decoloration of a solution at a concentration of 40 mg/L, showing an excellent reaction rate constant and a decoloration percentage of 86.15%.

Variability of the components of oil drilling waste according to the treatment temperature

L.L. Vázquez-Vázquez — 2023-03-15

In Mexico's hydrocarbon sector, drilling waste represents a problem because the techniques to treat it increase production costs and although thermal desorption represents a good option, it presents variations in removals. For these reasons, these variations were evaluated according to the treatment temperature (< 320 ° C) on a laboratory scale. It was observed that the samples have minerals in common (quartz, barite, and calcium sulfate) and these do not vary after treatments, but other minerals were observed that are present in some samples and not in others. It was also observed that the hydrocarbons decrease with respect to the temperature, but when comparing the removed percentages and the fractions, they are different between the samples; likewise, Cd, Cr, Pb, Ni, Zn, V, Ba, Fe, and Mn were detected, but their concentration in the leachates is low. It is concluded that the variation in the constituents of the drilling cuttings could depend on the source of generation and that this factor could influence the final properties of the treated solid since although the removal of hydrocarbons is achieved, the fractions present, and the concentration of metals are different between the samples

Phytoabsorption of heavy metals from leachates using the species Cyperus laxus and Chrysopogon zizanioides

S.G. Cahuich-Flores — 2023-03-15

This study aimed to evaluate and compare the phytoremediation potential of Cyperus laxus and Chrysopogon zizanioides, exposed to a mixture of leachates containing heavy metals. C. laxus is a native species from Mexico and C. zizanioides is an introduced species. Exposure to the leachate was performed using concentration kinetics concerning exposure times (TE) (Control 1, Control 40, 1,7, 15, 30, and 40 days). For this purpose, a completely randomized two-factor design with a 2x7 arrangement in triplicate was performed. The data were analyzed by ANOVA followed by an LSD multiple range test. For the quantification of metals in leachate and plants, inductively coupled plasma atomic emission spectroscopy (ICP-OES) was used. Ten chemical elements (Al, As, Ba, Cr, Hg, Ni, Pb, Se, Tl, and Zn) were identified in leachate and plants. It was observed that C. laxus absorbed mostly Al, Ba, Cr, Cr, Hg, and Ni, while C. zizanioides absorbed As, Pb, Se, Tl, and Zn. In translocation factor (TF) calculations C. laxus translocated only As, whereas C. zizanioides translocated As>Tl>Ba>Cr>Ni, respectively.

Determination of interfacial energy of the system acetylsalicylic acid-ethanol using the 3D nucleation theory and the integral method

X.M. Medina-Galvan — 2022-12-12

In this work, the interfacial energy of the acetylsalicylic acid-ethanol system was evaluated using experimental results of the metastable zone width (MSZW) obtained at different operation conditions: agitation rate (230 and 400 rpm), cooing rate (6, 9 12 and 15 K/h) and saturation temperature (288.15, 293.15, 298.15, 303.15, 308.15 and 313.15 K). A nonlinear regression algorithm and a simple to implement lineal integration approach of the number density of nuclei were used to determine the interfacial energy. The results obtained with the two integral strategies were compared with the values obtained with the 3D nucleation theory. Estimations obtained with the nonlinear regression presented a difference smaller than 6.5 % but estimations determined with the lineal integration approach had an average difference of 48.6 %.

Influence on pretreatment in CeO2 and Au/CeO2 catalyst to improve the creation of surface defects enabling modification in optical interband.

M.X. Cordero-García — 2022-12-13

Cerium oxide as a material within heterogeneous catalysis remains a relevant research topic due to its redox behavior, directly related to the presence of oxygen vacancies (Vo-) which are responsible for ceria’s high oxygen storage capacity. CeO₂ also have been employed as a support for active noble metal particles; in particular, supported gold catalyst has been proposed as a candidate to be used in different reactions such as CO oxidation, catalytic combustion of hydrocarbons, WGS reaction, among others. Despite its relevance, few works have a detailed understanding of the pretreatment effect on these catalysts. For this reason, in this work, we study the in situ behavior of CeO₂ and Au/CeO₂ during different pretreatments in temperature and atmosphere by Raman and Diffuse reflectance UV-Vis. These techniques allow us to follow in real-time the surface changes of Au nanoparticles and CeO₂. We demonstrate a direct correlation lattice structural defects of CeO₂ with modifications formed by electronic states in the optical interband and, the deposition of Au nanoparticles on the surface of CeO₂ allows to improve the properties formed by the electronic states between the valence band and the conduction band by increasing more than twice the structural defects compared to CeO₂ alone.

Comparative study of the prediction of electrical energy from a photovoltaic system using the intelligent systems ANFIS and ANFIS-GA

L.O. Lara-Cerecedo — 2023-01-06

Electrical energy generation with hydrocarbons accounts for about 38% of global CO₂ emissions. Solar photovoltaic technology is a reliable alternative to reduce these emissions. To predict the electrical energy generation behavior in a photovoltaic system, we developed an adaptive neuro-fuzzy inference system (ANFIS) model which integrates an optimization through a genetic algorithm (GA). The evolutionary ANFIS-GA uses a geographical area's solar radiation and ambient temperature. This model uses the capacity for classification and identification of data patterns of neural networks, and through fuzzy modeling, it calculates the optimal membership functions and fuzzy rules. The ANFIS-GA model is developed using MATLAB® software and is trained with the acquired data weather station and the electrical power output of the photovoltaic system located in Hermosillo, Sonora, México. The above was compared under the same parameters with an ANFIS model based on a hybrid algorithm. Reach values of RSME of 259.41, MAE of 132.7, MAPE of 4.56 for the ANFIS-GA model; RSME of 295.26, MAE of 149.58, and MAPE of 6.98 for the ANFIS model, respectively. The results indicate that the ANFIS-GA model emulates the power output with better precision, thus providing a valuable planning tool to predict photovoltaic system behavior.

A comparative study of different poly(3-hexylthiophene)–carbon based hole transport layers on the stability of perovskite solar cells prepared under ambient conditions

C.F. Arias-Ramos — 2023-03-13

Hole transport layers (HTLs) play an important role in efficiency and stability of perovskite solar cells (PSCs). Most of the highly efficient PSCs use spiro-OMeTAD doped with Li-TFSI as HTLs, which has to be prepared under inert atmosphere, because the hygroscopic feature of the lithium salt deteriorates the stability of PSCs under ambient conditions. In this work, we report a comparative study of the electrical and morphological properties of different poly(3-hexylthiophene) (P3HT) thin films: pristine, doped with FeCl₃, and composites with carbon nanotubes (CNT) or reduced graphene oxide (rGO). Although the electrical conductivity of P3HT films is found to increase with any of those modification methods, the photovoltaic performance of PSCs is highly dependent on the modification agent. P3HT:FeCl₃ reduces the photocurrent density of PSCs, while the addition of rGO in P3HT improves charge extraction and stability of PSCs. Furthermore, the insertion of conductive carbon paint between P3HT and the metal contact maintains the original efficiency of non-encapsulated PSCs after continuous illumination for 30 min. It is concluded that carbon modifications in P3HT based HTL can improve the stability of perovskite solar cells totally fabricated under ambient conditions.