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La nanotecnología es considerada como la revolución industrial del siglo XXI, por esto la obtención y aplicación de nanopartículas (NPs) es de vital interés para muchos rubros de la ciencia e industria. El uso de las NPs-Fe3O4 obtenidas por síntesis verde se extiende desde la cosmética, medicina, remediación ambiental, eléctrica y electrónica, debido a sus características térmicas, ópticas y magnéticas, sin mencionar el bajo costo de producción. En esta revisión se analizan los factores con mayor efecto durante la síntesis de NPs-Fe3O4 como lo son el pH, la temperatura, el tiempo, la cantidad de precursores metálicos y cantidad de metabolitos secundarios; variables que afectan de manera directa el tamaño, forma y morfología de las NPs-Fe3O4.

Bismuth is one of the most difficult impurities to remove in mining concentrates and low concentrations generate problems in silver and copper refineries. Therefore, financial penalties are established when concentrations exceed 0.05%. Some researchers had used arsenic to remove bismuth with results of up to 52% of extraction. Unfortunately, this mechanism is not yet fully understood. The objective of this research was to obtain the solubility parameters of amorphous mineral compounds, including bismuth-based compounds, through computational simulation using molecular dynamics. The composition of the mineral sample was determined by X-ray diffraction and the crystalline species were obtained and modeled using Materials Studio software. The nanostructures were optimized by an energy minimization methodology using the Broyden-Fletcher-Goldfarb-Shanno algorithm and were validated using the figure of merit equation and density. Simulations were performed using the Universal Force Field at constant pressure and temperature. The results of the minerals identified in the sample were compared with arsenic trioxide, indicating miscibility between As2O3and Bi2O3, possible miscibility with 10 other minerals, and immiscibility with the rest. The results indicate that As2O3 can be successfully used for the removal of Bi2O3 without a negative effect on the recovery of other minerals of higher commercial value.

Microbial production of aroma compounds is a promising alternative to extracting plants or chemical synthesis. The yeast Pichia fermentans ITD-00165 has demonstrated a high potential to produce isoamyl acetate. The yeast was cultured in a bioreactor on a chemically defined medium to evaluate the influence of airflow (0.5, 0.75, and 1.0 vvm) and agitation speed (150, 175, and 200 rpm) on the isoamyl acetate production. Isoamyl acetate was retained using an in situ entrapping system, which was obtained, adding a cap of n-decane in a ratio of 80:20 (medium:decane). This work demonstrated the relevance of well-controlled aeration to enhance isoamyl acetate production using isoamyl alcohol as a precursor. Culture operating near to 0.71 vvm and 168 rpm (kLa = 0.16 min-1) achieved production of 2.14 g L-1, which means an almost 2.5-fold increase in respect to the higher value previously reported. On the other hand, the minimum production occurred at the best aeration conditions (kLa = 0.22 min-1), meaning that excessive aeration could negatively affect the aroma production. Nevertheless, it appears that the concomitant ethanol production negatively affects aroma production.

The enzymatic conversion of lignocellulosic biomass to fermentable sugars is determined by the enzymatic activity of cellulases; consequently, improving enzymatic activity has attracted great interest in the scientific community. Cocktails of commercial cellulase often have low β-glucosidase content, leading to the accumulation of cellobiose. This accumulation inhibits the activity of the cellulolytic complex and can be used to determine the enzymatic efficiency of commercial cellulase cocktails. Here, a novel codon optimized β-glucosidase gene (B-glusy) from Trichoderma reesei QM6a was cloned and expressed in three strains of Escherichia coli (E. coli). The synthetic sequence containing an open reading frame (ORF) of 1491 bp was used to encode a polypeptide of 497 amino acid residues. The β-glucosidase recombinant protein that was expressed (57 kDa of molecular weight) was purified by Ni agarose affinity chromatography and visualized by SDS-PAGE. The recombinant protein was better expressed in E. coli BL21 (DE3), and its enzymatic activity was higher at neutral pH and 30 °C (22.4 U/mg). Subsequently, the β-glucosidase was immobilized using magnetite nano-support, after which it maintained >65% of its enzymatic activity from pH 6 to 10, and was more stable than the free enzyme above 40 °C. The maximum immobilization yield had enzyme activity of 97.2%. In conclusion, β-glucosidase is efficiently expressed in the microbial strain E. coli BL21 (DE3) grown in a simplified culture medium.

This review presents important information about general aspects of the mining process as a source of environmental pollution, economic and health impact, microorganisms involved in the microenvironments resulting from ore exploitation, and resistance mechanisms to As and Zn, as a global vision of topics of interest to researchers or students involved in this field. The exploitation of mineral resources generates ideal but extreme microenvironments, where the growth of microorganisms adapted to high concentration levels of heavy metals in comparison to common soil occurs; tailings, contaminated soils, and acid mine drains are sources of culturable heavy metal–resistant microorganisms that naturally grow under stressful conditions. The present review focuses on As and Zn as heavy metal pollutants, due to their presence in high concentrations in mining wastes, regardless of geographic location and mineral processes, in addition to their toxicity; the low profile of Zn as a pollutant even at the alarming levels can be found in mining wastes and consequently in the environment; the impact of ore processing is also included and provides an overview of some of the data on the relationships of mining microbiology highlighting the potential of microorganisms to eliminate these compounds discharged by any means into the environment. The relevance of this compendium is to highlight the interaction of native microorganisms present in mining wastes with high concentrations of heavy metals (As and Zn) as a biological treatment to remove such contaminants as an alternative to conventional technologies.

Recently, biotechnological opportunities have been found in non-Saccharomyces yeasts because they possess metabolic characteristics that lead to the production of compounds of interest. It has been observed that Kluyveromyces marxianus has a great potential in the production of esters, which are aromatic compounds of industrial importance. The genetic bases that govern the synthesis of esters include a large group of enzymes, among which the most important are alcohol acetyl transferases (AATases) and esterases (AEATases), and it is known that some are present in K. marxianus, because it has genetic characteristics like S. cerevisiae. It also has a physiology suitable for biotechnological use since it is the eukaryotic microorganism with the fastest growth rate and has a wide range of thermotolerance with respect to other yeasts. In this work, the enzymatic background of K. marxianus involved in the synthesis of esters is analyzed, based on the sequences reported in the NCBI database.

The removal of total petroleum hydrocarbons (TPHs) from contaminated mining soil was carried out under in vitro conditions. The aerobic consumption of TPH in the slow bioremediation stage via biostimulation with native microorganisms and biostimulation-bioaugmentation with autochthonous fungal isolates was evaluated. The initial TPH concentration was 70,880 ± 975 mg TPH/kg soil, soil was amended with nutrients at a C:N:P ratio of 100:15:1, the water content was adjusted to the soil field capacity, and batch microcosm reactors were incubated at room temperature (20.5 ± 3.1°C) for 90 days. The bioaugmentation process was tested using four hydrocarbonoclastic fungal strains isolated from the same contaminated mining soil individually and a mixed culture of the four isolates. The molecular characterization of the isolated fungi was based on sequence analysis of 18S rRNA, and the fungi were identified as Aspergillus niger MT786339.1, Aspergillus fumigatus MT786338.1, Aspergillus terreus MT786341.1, and Aspergillus flavus MT786340.1. The best TPH removal was achieved by inoculation with the fungal consortium (57 ± 1.97%) at 45 days (slow stage) after initiating the biostimulation process, followed by inoculation with Aspergillus niger (49 ± 1.2%), Aspergillus terreus (44 ± 0.67%), Aspergillus fumigatus (35 ± 0.98%), and Aspergillus flavus (32 ± 0.38%), while the degradation rate achieved with native microorganisms was only 21.6 ± 1.5%; statistical analysis of the results showed significant differences.

The search for microbial enzymatic activities applied to wastewater treatment is an important task in environmental biotechnology. Microbial enzymes have been previously explored in hostile habitats. They are increasingly important in extreme habitats; biological wastewater from the pulp and paper mill industry can harbor microorganisms with valuable enzymatic capabilities that can improve the efficiency for the same process of depuration. This study was performed to characterize and evaluate cellulolytic, amylolytic, and lipolytic activities of bacteria isolated from a pulp and paper effluent. The enzymatic activities were evaluated by the formation of a clear halo around the colonies in defined substrate media. By the use of a sequence analysis of 16S rDNA libraries, isolates were identified. The 16S rDNA libraries belong to the Bacillus subtilis, B. megaterium, B. licheniformis, B. pumilus, B. thuringiensis, B. cereus, Chryseobacterium daecheongense, and Microbacterium sediminis (an alkali-tolerant bacteria which has only been isolated from deep-sea sediment). B. cereus was the best strain for cellulose and lipase activities; moreover, C. daecheongense was best for amylase activity. The present study shows that the aerated lagoons from the pulp and paper industry are a promising source of bacterial with different enzyme activities. This data is relevant for industrial applications.

Recently, biotechnological opportunities have been found in non-Saccharomyces yeasts because they possess metabolic characteristics that lead to the production of compounds of interest. It has been observed that Kluyveromyces marxianus has a great potential in the production of esters, which are aromatic compounds of industrial importance. The genetic bases that govern the synthesis of esters include a large group of enzymes, among which the most important are alcohol acetyl transferases (AATases) and esterases (AEATases), and it is known that some are present in K. marxianus, because it has genetic characteristics like S. cerevisiae. It also has a physiology suitable for biotechnological use since it is the eukaryotic microorganism with the fastest growth rate and has a wide range of thermotolerance with respect to other yeasts. In this work, the enzymatic background of K. marxianus involved in the synthesis of esters is analyzed, based on the sequences reported in the NCBI database.

Water hyacinth (Eichhornia crassipes) is an aquatic flowering plant that belongs to the Pontederiaceae family. The plant is a freshwater hydrophyte that grows in subtropical and tropical regions of the world. The objective of this study was to determine the physicochemical characterization of roots, stems, and leaves of E. crassipes. The pH, ash, 1% alkali solubility, extractives, lignin, holocellulose, tannins, and calorific value were determined. Our results showed that the mineral content is relatively high, whereas that for lignin and tannins is low. The pH is moderately acid, and the soluble substances easily dissolved in alkali or organic solvents. Potassium, calcium, and silicon are the major constituents present in the ash of this plant. The determined calorific value was approximately 14.4 MJ/kg.

This study was conducted with a fungal strain isolated from a mining soil contaminated with total petroleum hydrocarbons (TPH) and properly identified by pol...

The goal of this study was to evaluate the effect of high Tween 80 concentrations on hydrocarbon contaminants and hydrocarbonoclastic microorganisms present in contaminated mining soil during a bioremediation process. The independent variables included Tween 80 concentration and process time. The elected response variables included concentration of total petroleum hydrocarbons (TPH), the chemical composition of contaminants, viable microbial count, and CO2 production. These were measured at various time points during the bioremediation process, which was conducted at room temperature. Higher removal of pollutants occurred at low Tween 80 concentrations. An analysis of the normalized variables shows that the rate of TPH degradation depended on microbial growth rate, which depended on Tween 80 concentration. The addition of Tween 80 changed the concentration and type of the residual hydrocarbon contaminants present, as well as the count and genus of the hydrocarbonoclastic microorganisms that grew during the bioremediation process. Higher concentrations of Tween 80 increased the levels of the chemical compounds present in the bioremediated soil while reducing the viable count and microbial diversity during the bioremediation process. Conversely, low Tween 80 concentrations produced only monoethylhexyl phthalate, which is not a petroleum hydrocarbon derivative. Overall, these results prove that the removal of TPH is dependent on the count and genus of active indigenous hydrocarbonoclastic microorganisms in soil, and these conditions may be controlled by modulating the concentration of Tween 80 that is applied.

International audience; This study deals with the production of isoamyl acetate (IAA) by fermentation of sugar cane molasses with the strain Pichia fermentans ITD00165, using L-leucine as precursor. A mathematical model that describes the experimental data from fermentation was developed for its use as a tool for further process optimization. The fermentation system was constantly aerated and coupled to liquid–liquid in situ extraction with decane as the recovery solvent. Thus, the model integrates the biological production of IAA, its partition coefficient in the two liquid phase system and the stripping effect of aeration. A productivity of 26 mg L−1 h−1 was obtained with addition of 4 g L−1 of L-leucine at 12 h of fermentation. The use of the model for process optimization was explored. According to it, the maximum theoretical productivity that can be obtained is 63 mg L−1 h−1. The model was used to determine that 1.6 g L−1 is the minimum concentration of L-leucine that can be added without significantly reducing IAA production. Also, it makes possible to propose an adequate decane/culture medium ratio, to have a desired final concentration and amount of recovered IAA. This value can be adjusted based on the needs of further purification steps and is useful to define a global economic optimum of the process.

Agave plants are members of the Agavaceae family and utilize crassulacean acid metabolism (CAM) for CO2 fixation. Fructans are the main photosynthetic products produced by Agave plants, and are their principal source of storage carbohydrates. The aim of this work was to determine the chemical and molecular characterization of fructans from Agave durangensis. Fructans were extracted from 10 year old A. durangensis plants. Trimethylsilyl derivatization was employed to determine the monomer composition. The linkage types in these carbohydrates were determined by methylation followed by reduction and O-acetylation, and finally analysis by gas chromatography-mass spectrometry (GC-MS). Samples were shown to contain t-β-D-Fruf, t-α-D-Glup, i-α-D-6-Glup and 1,6-di-β-D-Fruf linkages. The analysis of the degree of polymerization (DP) was confirmed by MALDI-TOF-MS, showing a wide DP ranging from 2 to 29 units. The analyses performed revealed that fructans from A. durangensis are formed of 97.11% fructose and 2.89% glucose, and are a complex mixture of fructooligosaccharides of the neo-fructan type containing principally β(2-1) and β(2-6) linkages, with branch moieties. Key words: Degree of polymerization (DP), GC-MS, MALDI-TOF-MS.

Twelve strains of fungi from residues of Agave durangensis were isolated and identified by molecular techniques for evaluation of their hydrolytic enzyme production capability. A proportion (50%) of the fungal strains belonged to the Aspergillus genus and the other strains used belonged to Alternaria, Neurospora crassa, Mucor sp, Rhizopus sp., Botryosphaeria sp., and Scytalidium sp. The isolated strains were evaluated for their potential to produce extracellular enzymes using different substrates (cellulose, xylan, inulin, Agave fructans, starch, and tannic acid). It was observed that most of the tested strains were capable of simultaneously secreting cellulases, xylanases, inulinases, fructanases, and laccases. Botryosphaeria sp. ITD-G6 was selected for its evaluation in the production of inulinase, using different substrates. Showing high inulinase activities (5.22 U / mL for Agave waste, 4.37 U/ mL for inulin and 5.00 U / mL for Agave fructans).

The dimeric enzyme β-glucosidase from Aspergillus niger has been immobilized on different amino-agarose beads at pH 5 and 7, exploiting the versatility of glutaraldehyde. The stability of the free enzyme depended on enzyme concentration. Immobilization via ion exchange improved enzyme stability/activity, depending on the immobilization pH. However, the enzyme was desorbed in 75 mM NaCl at pH 7 and some stability/enzyme concentration dependence still existed. Treatment: of these biocatalysts with glutaraldehyde increased enzyme stability (e.g. at pH 5, after incubation under conditions where the enzyme just ionically exchanged was fully inactivated, the activity of the glutaraldehyde treated enzyme remained unaltered). Immobilization on glutaraldehyde pre-activated supports yielded a higher increase in enzyme activity, but the stabilization was lower. While when measuring the enzyme activity at pH 4 there were no changes after immobilization, all immobilized enzymes were more active than the free enzyme at pH 6 and 7 (2–3 times). The Ki/Km ratio did not significantly decrease in any immobilized biocatalysts, and in some cases it worsened in a significant way (by a 9 fold factor using preactivated supports). The new biocatalysts are significantly more stable and avoid enzyme subunit desorption, being the immobilization pH a key point in their design.

Aerated lagoons are a main unit operation for wastewater treatment in the paper industry. Many such operations involve inoculation with bacterial formulations in which in situ effectiveness has not been proven; this can be translated into low efficiency in treatment and unnecessary investments. Lack of knowledge of bacterial biodiversity present in a lagoon limits the capacity to exploit the maximum degradation. To overcome such problems, various methods to identify and study these microorganisms have been developed. In this study, a PCR-DGGE analysis was performed to estimate the bacterial diversity and to verify the presence of bacteria present in a commercial inoculum in two aerated lagoons of a pulp and paper effluent. Phylogenetic affiliation of predominant member’s correspondent to γ- and β-proteobacteria and Firmicutes were found. The dominant bacteria present in lagoon 2 belonged to the following genus Microbacterium sp. Rhodocyclaceae sp., Eubacterium sp. and B. subtilis. In lagoon 1 the dominant genus included Microbacterium sp., Rhodocyclaceae sp. Tepidimonas sp., Acetanaerobacterium sp., and Flavobacteria sp. The two characterized lagoons were not similar to the commercial inoculum. In addition, non-dominant bacteria (less relative intensity) were composed mostly of bacteria of the commercial inoculum.

Fermentation with filamentous fungi in a bioreactor is a complex dynamic process that is affected by flow conditions and the evolution of the rheological properties of the medium. These properties are mainly affected by the biomass concentration and the morphology of the fungus. In this work, the rheological properties of a fermentation with the fungus Beauveria bassiana under different hydrodynamic conditions were studied and the rheological behavior of this broth was simulated through a mixture of carboxymethyl cellulose sodium and cellulose fibers (CMCNa-SF). The bioreactor was a 10 L CSTR tank operated at different stir velocities. Rheological results were similar at 100 and 300 rpm for both systems. However, there was a significant increase in the viscosity accompanied by a change in the consistence index, calculated according to the power law model, for both systems at 800 rpm. The systems exhibited shear-thinning behavior at all stir velocities, which was determined with the power law model. The mixing time was observed to increase as the cellulose content in the system increased and, consequently, the efficiency of mixing diminished. These results are thought to be due to the rheological and morphological similarities of the two fungal systems. These results will help in the optimization of scale-up production of these fungi.

The performances of radial-axial flow (Rushton-Maxflo impellers) and axial-radial flow (Maxflo-Rushton impellers) mixers in the laminar-transitional flow regime were experimentally and numerically investigated with Newtonian and non-Newtonian fluids. The rheological properties for a fermentation broth consisting of the fungus Beauveria bassiana were studied under different hydrodynamic conditions in these systems. The bioreactor was a continuous stirred-tank reactor (CSTR), set at different stirring velocities. The rheology of the systems exhibited shear-thinning behavior which was modeled with the power law model. The experimental hydrodynamics and configuration modes were compared and simulated with a model fluid system and by numerical criteria (computational fluid dynamics). The R-M mode was found to be more efficient than the M-R rotating mode in terms of energy and homogenization time. The results will help in the optimization of scale-up production of these fungi.

El poder calorífico y el contenido de sustancias minerales (cenizas) se determinaron en la corteza de seis especies arbóreas frutales (Annona cherimola Mill., Citrus aurantifolia Swingle, Malus domestica Borkh., Psidium guajava L., Prunus dulcis [Mill.] D. A. Webb y Tamarindus indica L.). Las cenizas obtenidas fueron analizadas mediante rayos X. Los valores encontrados de poder calorífico variaron de 3,453.49 kcal•kg-1 en T. indica a 4,076.10 kcal•kg-1 en P. guajava. En el caso de las cenizas, los resultados fluctuaron de 5.76 % en P. guajava a 21.93 % en T. indica. Se observó que un contenido mayor de minerales en las cortezas tiende a disminuir su poder calorífico. Los elementos químicos comunes en las muestras analizadas fueron calcio, potasio, magnesio, fósforo y azufre. No se detectaron metales pesados en las muestras de la corteza.

The iron concentrate from Hercules Mine of Coahuila, Mexico, which mainly contained pyrite and pyrrhotite, was treated by the bioleaching process using native strain Acidithiobacillus ferrooxidans (A. ferrooxidans) to determine the ability of these bacteria on the leaching of zinc. The native bacteria were isolated from the iron concentrate of the mine. The bioleaching experiments were carried out in shake flasks to analyze the effects of pH values, pulp density, and the ferrous sulfate concentration on the bioleaching process. The results obtained by microbial kinetic analyses for the evaluation of some aspects of zinc leaching show that the native bacteria A. ferrooxidans, which is enriched with a 9K Silverman medium under the optimum conditions of pH 2.0, 20 g/L pulp density, and 40 g/L FeSO4, increases the zinc extraction considerably observed by monitoring during15 d, i.e., the zinc concentration has a decrease of about 95% in the iron concentrate.

Effects of geometry and Reynolds number on the production of essential oil were investigated. Experiments, performed on an oregano packed bed, were designed to reproduce expected plant operating conditions. A diffusive model was found to apply to oil extraction and effective diffusion coefficients were calculated as a function of the bed L / D ratio and Reynolds number. Effective diffusivities were found to be of the same order of magnitude as those for drying of similar materials (≅10 −9 m 2 /s). Statistical analysis showed that Re effects are more important, but that extraction is also affected by L / D variations. Application of this information to select the optimum operation parameters needs additional plant-specific, cost-related data.

Con el propósito de aprovechar un recurso que en la actualidad es un desecho contaminante generado durante el aserre de la madera en Durango, México, se probaron los métodos de pretratamiento alcalino, ácido y explosión con vapor a temperatura de autoclave, para realizar la hidrólisis enzimática de aserrín de pino obtenido de tres aserraderos de la ciudad de Durango y recuperar los azúcares contenidos en él. Se encontró que el pretratamiento con NaOH a 120 ºC proporciona mejores resultados que los tratamientos con ácido sulfúrico diluido y por explosión con vapor a 121 ºC. Se optimizó el pretratamiento alcalino por el método de superficie de respuesta. Los resultados muestran que la concentración óptima de azúcares reductores, con un valor de 48 %, se obtuvo después de un pretratamiento con 8 % de NaOH durante 85 minutos a 120 ºC, a un pH de hidrólisis de 4.5, durante 240 h, con una carga enzimática de 25 UPF/g de carbohidratos totales. Por comparación con los resultados reportados en la literatura, se encuentra que el procedimiento obtenido es susceptible de ser utilizado para el aprovechamiento de este recurso.

This study was performed to evaluate the chemical composition and in vitro gas production of five agro-industrial residues, with and without treatment, using solid substrate fermentation. Oat straw, bean straw, corn stubble, apple pomace and agave bagasse were treated using two filamentous fungi, Trichoderma harzianum and Phanaerochaete chrysosporium. Chemical analyses (crude protein, neutral detergent fiber, acid detergent fiber, lignin, cellulose and hemicellulose) were carried out. Calibrated glass syringes were used for in vitro gas production determinations and volatile fatty acid (VFA) profile was obtained by gas chromatography. In vitro data were fitted using the equations p=a+b(1-e-ct) by Ørskov and McDonald and G=A/(1+[B/t]) by France et al (2000). Increases in CP content (P0.05) were registered by treating oat straw (20%), bean straw (83%) and corn stubble (16%) with P. chrysosporium. Contents of NDF were reduced by 9.5% in oat straw by treatments (P0.05). Regarding gas production parameters, the b value in agave bagasse (57.4%) and gas production rate constant c (7.5%) were higher (P0.05) in the substrate treated with P. chrysosporium related to other treatments. Similarly, higher values for the A parameter were registered in maize straw (+22%) and agave bagasse (+13%) treated with P. chrysosporium. In spite of these isolated differences, the analysis performed showed that the chemical composition, mainly structural carbohydrates, were not modified under the conditions of this study.

Facultad de Ingeniería en Tecnología de la Madera. Ciencias y Tecnología de la Madera In order to take advantage of a waste product such as pine sawdust from a sawmill in Michoacán, Mexico, five different pretreatments (sodium hydroxide, sulfuric acid, steam explosion, organosolv and nitric acid) for the production of sugars were tested reducing by enzymatic hydrolysis. We found that pretreatment with HNO3 to 6% and NaOH to 1% achieve better yields than sodium hydroxide, dilute sulfuric acid, steam explosion and organosolv. HNO3 yields were optimized by factorial method. The results show that the optimum concentration of reducing sugar, with a value of 35.42% after pretreatment with 9.63% of HNO3 solution at 114.81°C of temperature followed by 1 % NaOH for 30 minutes at 90°C, at a pH of 4.5, for 132 hours with an enzyme load of 25 FPU/g total carbohydrates. Simultaneous scarification and fermentation one became resulting in a concentration of 27.39 g/L of ethanol and a maximum theoretical yield of 73.61% a pH of 3.5, 150 rpm with Saccharomyces cerevisiae 1X107 Cel/mL and enzyme load of 25 FPU/g total carbohydrate. With the results obtained from the literature, we find that is susceptible to being used for the exploitation of this resource. Con el propósito de aprovechar un producto de desecho como es el aserrín de pino proveniente de un aserradero en Michoacán, México, se probaron cinco diferentes pretratamientos (Hidróxido de sodio, ácido sulfúrico, Explosión de vapor, organosolv y ácido nítrico) para la producción de azúcares reductores por medio de hidrolisis enzimática. Se encontró que el pretratamiento con HNO3 al 6% y NaOH al 1% proporcionó mejores rendimientos que el hidróxido de sodio, ácido sulfúrico diluido, explosión de vapor y organosolv. Se optimizaron los rendimientos del HNO3 por el método factorial. Los resultados muestran que la concentración óptima de azúcares reductores, con un valor de 35.42% después de un pretratamiento con 9.63% de HNO3 a temperatura de 114.81°C seguido de 1% NaOH durante 30 minutos a 90°C, a un pH de 4.5, durante 132 horas con una carga enzimática de 25 UPF/g de carbohidratos totales. Se hizo una sacarificación y fermentación simultánea obteniendo como resultado una concentración de 27.39 g/L de etanol y un rendimiento teórico máximo de 73.61% a pH de 3.5, 150 revoluciones con 1X107Cel/mL de Saccharomyces cerevisiae y una carga enzimática de 25 UPF/g de carbohidratos totales. Con los resultados obtenidos de la literatura, se encuentra que es un procedimiento susceptible a ser usado para el aprovechamiento de este recurso.