Acetone–Butanol–Ethanol Production from Waste Seaweed Collected from Gwangalli Beach,Busan, Korea,Based on pH-Controlled and Sequential Fermentation Using Two Strains

The optimal conditions for acetone–butanol–ethanol (ABE) production were evaluated using waste seaweed from Gwangalli Beach, Busan, Korea. The waste seaweed had a fiber and carbohydrate, content of 48.34%; these are the main resources for ABE production. The optimal conditions for obtaining monosaccharides based on hyper thermal (HT) acid hydrolysis of waste seaweed were slurry contents of 8%, sulfuric acid concentration of 138 mM, and treatment time of 10 min. Enzymatic saccharification was performed using 16 unit/mL Viscozyme L, which showed the highest affinity (K_m?=?1.81 g/L). After pretreatment, 34.0 g/L monosaccharides were obtained. ABE fermentation was performed with single and sequential fermentation of Clostridium acetobutylicum and Clostridium tyrobutyricum; this was controlled for pH. A maximum ABE concentration of 12.5 g/L with Y_ABE 0.37 was achieved using sequential fermentation with C. tyrobutyricum and C. acetobutylicum. Efficient ABE production from waste seaweed performed using pH-controlled culture broth and sequential cell culture.     

Direct Fermentation of Gelatinized Cassava Starch to Acetone,Butanol, and Ethanol Using Clostridium acetobutylicum Mutant Obtained by Atmospheric and Room Temperature Plasma

The mutant strain designated as ART18, obtained from the wild-type strain Clostridium acetobutylicum PW12 treated by atmospheric and room temperature plasma, showed higher solvent tolerance and butanol production than that of the wild-type strain. The production of butanol was 11.3?±?0.5 g/L, 31 % higher than that of the wild-type strain when it was used for acetone, butanol, and ethanol fermentation in P2 medium. Furthermore, the effects of cassava flour concentration, pH regulators, and vitamins on the ABE production were also investigated. The highest butanol production of 15.8?±?0.8 g/L and butanol yield (0.31 g/g) were achieved after the above factors were optimized. When acetone, butanol, and ethanol fermentation by ART18 was carried out in a 15-L bioreactor, the butanol production, the productivity of butanol, and the total solvent were 16.3?±?0.9, 0.19, and 0.28 g/L^/h, respectively. These results indicate that ART18 is a promising industrial producer in ABE fermentation.     

Recovery of butanol from model ABE fermentation broths using MFI adsorbent: a comparison between traditional beads and a structured adsorbent in the form of a film

Butanol, a promising biofuel, can be produced by ABE (acetone, butanol and ethanol) fermentation using e.g. Clostridium acetobutylicum. However, the butanol concentration in the resulting broth is limited to only ca. 20 g/L due to the toxicity for the microorganisms. This low product concentration demands an efficient recovery process for successful commercialization of this process. In this study, a structured adsorbent in the form of steel monolith coated with a silicalite-1 film was prepared using the in situ growth method. The adsorbent was carefully characterized by SEM and XRD. The performance of the adsorbent was evaluated by performing breakthrough experiments at room temperature using model ABE fermentation broths and the performance was compared with that of traditional adsorbents in the form of beads. The structured silicalite-1 adsorbent showed less saturation loading time as compared to commercial binder free silicalite-1 beads, reflecting the different dimensions of the columns used, set by experimental constraints. Studies of the desorption process showed that by operating at appropriate conditions, butanol with high concentration i.e. up to 95.2 wt% for butanol–water model system and 88.5 wt% for ABE fermentation broth can be obtained using the structured silicalite-1 adsorbent. Commercial silicalite-1 beads also showed good selectivity but the concentration of butanol in the desorbed product was limited to 70 % for the butanol–water model system and 69 % for ABE fermentation broth, probably as a result of entrained liquid between the beads.     

Production of Acetone–Butanol–Ethanol (ABE) in Direct Fermentation of Cassava by Clostridium saccharoperbutylacetonicum N1-4

In this work, acetone–butanol–ethanol (ABE) fermentation characteristics of cassava starch and cassava chips when using Clostridium saccharoperbutylacetonicum N1-4 was presented. The obtained results in batch mode using a 1-L fermenter showed that C. saccharoperbutylacetonicum N1-4 was a hyperamylolytic strain and capable of producing solvents efficiently from cassava starch and cassava chips, which was comparable to when glucose was used. Batch fermentation of cassava starch and cassava chips resulted in 21.0 and 19.4 g/L of total solvent as compared with 24.2 g/L of total solvent when using glucose. Solvent productivity in fermentation of cassava starch was from 42% to 63% higher than that obtained in fermentation using corn and sago starches in the same condition. In fermentation of cassava starch and cassava chips, maximum butanol concentration was 16.9 and 15.5 g/L, respectively. Solvent yield and butanol yield (based on potential glucose) was 0.33 and 0.41, respectively, for fermentation of cassava starch and 0.30 and 0.38, respectively for fermentation using cassava chips.     

A Novel Process for Direct Production of Acetone–Butanol–Ethanol from Native Starches Using Granular Starch Hydrolyzing Enzyme by Clostridium saccharoperbutylacetonicum N1-4

In this work, a new approach for acetone–butanol–ethanol (ABE) production has been proposed. Direct fermentation of native starches (uncooked process) was investigated by using granular starch hydrolyzing enzyme (GSHE) and Clostridium saccharoperbutylacetonicum N1-4. Even the process was carried out under suboptimal condition for activity of GSHE, the production of ABE was similar with that observed in conventional process or cooked process in terms of final solvent concentration (21.3?±?0.4 to 22.4?±?0.4 g/L), butanol concentration (17.5?±?0.4 to 17.8?±?0.3 g/L) and butanol yield (0.33 to 0.37 g/g). The production of solvents was significantly dependent on the source of starches. Among investigated starches, corn starch was more susceptible to GSHE while cassava starch was the most resistant to this enzyme. Fermentation using native corn starch resulted in the solvent productivity of 0.47 g/L h, which was about 15 % higher than that achieved in cooked process. On the contrary, uncooked process using cassava and wheat starch resulted in the solvent productivity of 0.30 and 0.37 g/L h, which were respectively about 30 % lower than those obtained in cooked process. No contamination was observed during all trials even fermentation media were prepared without sterilization. During the fermentation using native starches, no formation of foam is observed. This uncooked process does not require cooking starchy material; therefore, the thermal energy consumption for solvent production would remarkably be reduced in comparison with cooked process.     

Production of acetone butanol ethanol from degermed corn using Clostridium beijerinckii BA101

In this article we report on acetone butanol ethanol (ABE) fermentation characteristics of degermed corn when using Clostridium beijerinckii BA101. Recent economic studies suggested that recovery of germ from corn and hence corn oil would help to make the ABE fermentation process more economical. C. beijerinckii BA101 ferments corn mash efficiently to produce ABE under appropriate nutritional and environmental conditions. Corn mash contains germ/corn oil that is, possibly, ancillary to the production of butanol during the ABE fermentation process. Since the presence of corn oil is not a critical factor in solvent fermentation, it can be removed and this will allow for byproduct credit. Batch fermentation of degermed corn resulted in 8.93 g/L of total ABE production as compared with 24.80 g/L of total ABE when supplemented with P2 medium nutrients. During the course of the germ separation process, corn steeping is required prior to grinding and removing the germ. It is likely that some nutrients from the corn are leached out during the steeping process. This may reduce the rate of fermentation and impact the final concentration of butanol/ABE that can be achieved. Fermentation of degermed corn with corn steep liquor resulted in the production of 19.28 g/L of ABE.     

Ultrasound-Enhanced Recovery of Butanol/ABE by Pervaporation

The search for renewable sources of energy has led to renewed interests on the biochemical route for the production of butanol. Butanol production suffers from several drawbacks, mainly caused by butanol inhibition to the butanol-producing microorganism which makes it economically uncompetitive against the chemical process. One possible solution proposed is the in situ recovery of acetone–butanol–ethanol (ABE). Among the in situ recovery options, membrane processes like pervaporation have a great potential. Thus, the effects of temperature, feed concentration, and ultrasound irradiation on permeate concentration and permeation flux for the recovery of butanol/ABE by pervaporation from aqueous solutions were investigated in this study. In the butanol–water system, permeate butanol concentration as well as flux increased with an increase in temperature and butanol feed concentration. When pervaporation studies with ABE–water mixture were carried out at 60 °C for 2, 4, 8, 16, and 24 h, pervaporation profile revealed an optimal permeate concentration as well as permeation flux. Applications of ultrasound irradiation on pervaporation improved permeate concentration by about 23 g/L for both butanol and ABE. Ultrasound irradiation also improved butanol and ABE mass permeation flux by about 13 and 11 %, respectively.     

Optimal conditions for alkaline detoxification of dilute-acid lignocellulose hydrolysates

Alkaline detoxification strongly improves the fermentability of dilute-acid hydrolysates in the production of bioethanol from lignocellulose with Saccharomyces cerevisiae. New experiments were performed with NH₄OH and NaOH to define optimal conditions for detoxification and make a comparison with Ca(OH)₂ treatment feasible. As too harsh conditions lead to sugar degradation, the detoxification treatments were evaluated through the balanced ethanol yield, which takes both the ethanol production and the loss of fermentable sugars into account. The optimization treatments were performed as factorial experiments with 3-h duration and varying pH and temperature. Optimal conditions were found roughly in an area around pH 9.0/60°C for NH₄OH treatment and in a narrow area stretching from pH 9.0/80°C to pH 12.0/30°C for NaOH treatment. By optimizing treatment with NH₄OH, NaOH, and Ca(OH)₂, it was possible to find conditions that resulted in a fermentability that was equal or better than that of a reference fermentation of a synthetic sugar solution without inhibitors, regardless of the type of alkali used. The considerable difference in the amount of precipitate generated after treatment with different types of alkali appears critical for industrial implementation.     

Continuous Enzymatic Hydrolysis of Lignocellulosic Biomass with Simultaneous Detoxification and Enzyme Recovery

Recovering hydrolysis enzymes and/or alternative enzyme addition strategies are two potential mechanisms for reducing the cost during the biochemical conversion of lignocellulosic materials into renewable biofuels and biochemicals. Here, we show that enzymatic hydrolysis of acid-pretreated pine wood with continuous and/or fed-batch enzyme addition improved sugar conversion efficiencies by over sixfold. In addition, specific activity of the hydrolysis enzymes (cellulases, hemicellulases, etc.) increased as a result of continuously washing the residual solids with removal of glucose (avoiding the end product inhibition) and other enzymatic inhibitory compounds (e.g., furfural, hydroxymethyl furfural, organic acids, and phenolics). As part of the continuous hydrolysis, anion exchange resin was tested for its dual application of simultaneous enzyme recovery and removal of potential enzymatic and fermentation inhibitors. Amberlite IRA-96 showed favorable adsorption profiles of inhibitors, especially furfural, hydroxymethyl furfural, and acetic acid with low affinity toward sugars. Affinity of hydrolysis enzymes to adsorb onto the resin allowed for up to 92 % of the enzymatic activity to be recovered using a relatively low-molar NaCl wash solution. Integration of an ion exchange column with enzyme recovery into the proposed fed-batch hydrolysis process can improve the overall biorefinery efficiency and can greatly reduce the production costs of lignocellulosic biorenewable products.

Butanol Production from Cane Molasses by <Emphasis Type="Italic">Clostridium saccharobutylicum</Emphasis> DSM 13864: Batch and Semicontinuous Fermentation

Clostridium acetobutylicum strains used in most Chinese ABE (acetone–butanol–ethanol) plants favorably ferment starchy materials like corn, cassava, etc., rather than sugar materials. This is one major problem of ABE industry in China and significantly limits the exploitation of cheap waste sugar materials. In this work, cane molasses were utilized as substrate in ABE production by Clostridium saccharobutylicum DSM 13864. Under optimum conditions, total solvent of 19.80 g/L (13.40 g/L butanol) was reached after 72 h of fermentation in an Erlenmeyer flask. In a 5-L bioreactor, total solvent of 17.88 g/L was attained after 36 h of fermentation, and the productivity and yield were 0.50 g/L/h and 0.33 g ABE/g sugar consumption, respectively. To further enhance the productivity, a two-stage semicontinuous fermentation process was steadily operated for over 8 days (205 h, 26 cycles) with average productivity (stage II) of 1.05 g/L/h and cell concentration (stage I) of 7.43 OD₆₆₀, respectively. The average batch fermentation time (stage I and II) was reduced to 21−25 h with average solvent of 15.27 g/L. This study provides valuable process data for the development of industrial ABE fermentation process using cane molasses as substrate.     

Bioethanol Production from Soybean Residue via Separate Hydrolysis and Fermentation

Bioethanol was produced using polysaccharide from soybean residue as biomass by separate hydrolysis and fermentation (SHF). This study focused on pretreatment, enzyme saccharification, and fermentation. Pretreatment to obtain monosaccharide was carried out with 20% (w/v) soybean residue slurry and 270 mmol/L H₂SO₄ at 121 °C for 60 min. More monosaccharide was obtained from enzymatic hydrolysis with a 16 U/mL mixture of commercial enzymes C-Tec 2 and Viscozyme L at 45 °C for 48 h. Ethanol fermentation with 20% (w/v) soybean residue hydrolysate was performed using wild-type and Saccharomyces cerevisiae KCCM 1129 adapted to high concentrations of galactose, using a flask and 5-L fermenter. When the wild type of S. cerevisiae was used, an ethanol production of 20.8 g/L with an ethanol yield of 0.31 g/g consumed glucose was obtained. Ethanol productions of 33.9 and 31.6 g/L with ethanol yield of 0.49 g/g consumed glucose and 0.47 g/g consumed glucose were obtained in a flask and a 5-L fermenter, respectively, using S. cerevisiae adapted to a high concentration of galactose. Therefore, adapted S. cerevisiae to galactose could enhance the overall ethanol fermentation yields compared to the wild-type one.     

Effect of Nutrients on Fermentation of Pretreated Wheat Straw at very High Dry Matter Content by Saccharomyces cerevisiae

Wheat straw hydrolysate produced by enzymatic hydrolysis of hydrothermal pretreated wheat straw at a very high solids concentration of 30% dry matter (w/w) was used for testing the effect of nutrients on their ability to improve fermentation performance of Saccharomyces cerevisiae. The nutrients tested were MgSO₄ and nitrogen sources; (NH₄)₂SO₄, urea, yeast extract, peptone and corn steep liquor. The fermentation was tested in a separate hydrolysis and fermentation process using a low amount of inoculum (0.33 g kg^?1) and a non-adapted baker’s yeast strain. A factorial screening design revealed that yeast extract, peptone, corn steep liquor and MgSO₄ were the most significant factors in obtaining a high fermentation rate, high ethanol yield and low glycerol formation. The highest volumetric ethanol productivity was 1.16 g kg^?1 h^?1 and with an ethanol yield close to maximum theoretical. The use of urea or (NH₄)₂SO₄ separately, together or in combination with MgSO₄ or vitamins did not improve fermentation rate and resulted in increased glycerol formation compared to the use of yeast extract. Yeast extract was the single best component in improving fermentation performance and a concentration of 3.5 g kg^?1 resulted in high ethanol yield and a volumetric productivity of 0.6 g kg^?1 h^?1.     

Continuous production of butanol from starch-based packing peanuts

Acetone, butanol, ethanol (ABE, or solvents) were produced from starch-based packing peanuts in batch and continuous reactors. In a batch reactor, 18.9 g/L of total ABE was produced from 80 g/L packing peanuts in 110 h of fermentation. The initial and final starch concentrations were 69.6 and 11.1 g/L, respectively. In this fermentation, ABE yield and productivity of 0.32 and 0.17 g/(L·h) were obtained, respectively. Compared to the batch fermentation, continuous fermentation of 40 g/L of starch-based packing peanuts in P2 medium resulted in a maximum solvent production of 8.4 g/L at a dilution rate of 0.033 h⁻¹. This resulted in a productivity of 0.27 g/(L·h). However, the reactor was not stable and fermentation deteriorated with time. Continuous fermentation of 35 g/L of starch solution resulted in a similar performance. These studies were performed in a vertical column reactor using Clostridium beijerinckii BA101 and P2 medium. It is anticipated that prolonged exposure of culture to acrylamide, which is formed during boiling/autoclaving of starch, affects the fermentation negatively.     

Dark Fermentative Hydrogen Production from Neutralized Acid Hydrolysates of Conifer Pulp

Concentrated acid hydrolysis of cellulosic material results in high dissolution yields. In this study, the neutralization step of concentrated acid hydrolysate of conifer pulp was optimized. Dry conifer pulp hydrolysis with 55?% H₂SO₄ at 45?°C for 2?h resulted in total sugar yields of 22.3?C26.2?g/L. The neutralization step was optimized for solid Ca(OH)₂, liquid Ca(OH)₂ or solid CaO, mixing time, and water supplementation. The highest hydrogen yield of 1.75?mol?H₂/mol glucose was obtained with liquid Ca(OH)₂, while the use of solid Ca(OH)₂ or CaO inhibited hydrogen fermentation. Liquid Ca(OH)₂ removed sulfate to below 30?mg SO₄ ^2?/L. Further optimization of the neutralization conditions resulted in the yield of 2.26?mol?H₂/mol glucose.     

Improvement of Solvent Production from Xylose Mother Liquor by Engineering the Xylose Metabolic Pathway in Clostridium acetobutylicum EA 2018

Xylose mother liquor (XML) is a by-product of xylose production through acid hydrolysis from corncobs, which can be used potentially for alternative fermentation feedstock. Sixteen Clostridia including 13 wild-type, 1 industrial strain, and 2 genetically engineered strains were screened in XML, among which the industrial strain Clostridium acetobutylicum EA 2018 showed the highest titer of solvents (12.7 g/L) among non-genetic populations, whereas only 40 % of the xylose was consumed. An engineered strain (2018glcG-TBA) obtained by combination of glcG disruption and expression of the d-xylose proton-symporter, d-xylose isomerase, and xylulokinase was able to completely utilize glucose and l-arabinose, and 88 % xylose in XML. The 2018glcG-TBA produced total solvents up to 21 g/L with a 50 % enhancement of total solvent yield (0.33 g/g sugar) compared to that of EA 2018 (0.21 g/g sugar) in XML. This XML-based acetone–butanol–ethanol fermentation using recombinant 2018glcG-TBA was estimated to be economically promising for future production of solvents.     

Enzymatic Hydrolysis and Fermentation of Pretreated Cashew Apple Bagasse with Alkali and Diluted Sulfuric Acid for Bioethanol Production

The aim of this work was to optimize the enzymatic hydrolysis of the cellulose fraction of cashew apple bagasse (CAB) after diluted acid (CAB-H) and alkali pretreatment (CAB-OH), and to evaluate its fermentation to ethanol using Saccharomyces cerevisiae. Glucose conversion of 82?±?2 mg/g CAB-H and 730?±?20 mg/g CAB-OH was obtained when 2% (w/v) of solid and 30 FPU/g bagasse was used during hydrolysis at 45 °C, 2-fold higher than when using 15 FPU/g bagasse, 44?±?2 mg/g CAB-H, and 450?±?50 mg/g CAB-OH, respectively. Ethanol concentration and productivity, achieved after 6 h of fermentation, were 20.0?±?0.2 g L^?1 and 3.33 g L^?1 h^?1, respectively, when using CAB-OH hydrolyzate (initial glucose concentration of 52.4 g L^?1). For CAB-H hydrolyzate (initial glucose concentration of 17.4 g L^?1), ethanol concentration and productivity were 8.2?±?0.1 g L^?1 and 2.7 g L^?1 h^?1 in 3 h, respectively. Hydrolyzates fermentation resulted in an ethanol yield of 0.38 and 0.47 g/g glucose with pretreated CAB-OH and CAB-H, respectively. Ethanol concentration and productivity, obtained using CAB-OH hydrolyzate, were close to the values obtained in the conventional ethanol fermentation of cashew apple juice or sugar cane juice.     

Enhancing Clostridial Acetone-Butanol-Ethanol (ABE) Production and Improving Fuel Properties of ABE-enriched Biodiesel by Extractive Fermentation with Biodiesel

The extractive acetone–butanol–ethanol (ABE) fermentations of Clostridium acetobutylicum were evaluated using biodiesel as the in situ extractant. The biodiesel preferentially extracted butanol, minimized product inhibition, and increased production of butanol (from 11.6 to 16.5 gL⁻¹) and total solvents (from 20.0 to 29.9 gL⁻¹) by 42% and 50%, respectively. The fuel properties of the ABE-enriched biodiesel obtained from the extractive fermentations were analyzed. The key quality indicators of diesel fuel, such as the cetane number (increased from 48 to 54) and the cold filter plugging point (decreased from 5.8 to 0.2 °C), were significantly improved for the ABE-enriched biodiesel. Thus, the application of biodiesel as the extractant for ABE fermentation would increase ABE production, bypass the energy intensive butanol recovery process, and result in an ABE-enriched biodiesel with improved fuel properties.     

Ethanol Production from Sugarcane Bagasse Hydrolysate Using Pichia stipitis

The objective of this study was to evaluate the ethanol production from the sugars contained in the sugarcane bagasse hemicellulosic hydrolysate with the yeast Pichia stipitis DSM 3651. The fermentations were carried out in 250-mL Erlenmeyers with 100 mL of medium incubated at 200 rpm and 30 °C for 120 h. The medium was composed by raw (non-detoxified) hydrolysate or by hydrolysates detoxified by pH alteration followed by active charcoal adsorption or by adsorption into ion-exchange resins, all of them supplemented with yeast extract (3 g/L), malt extract (3 g/L), and peptone (5 g/L). The initial concentration of cells was 3 g/L. According to the results, the detoxification procedures removed inhibitory compounds from the hemicellulosic hydrolysate and, thus, improved the bioconversion of the sugars into ethanol. The fermentation using the non-detoxified hydrolysate led to 4.9 g/L ethanol in 120 h, with a yield of 0.20 g/g and a productivity of 0.04 g L^?1 h^?1. The detoxification by pH alteration and active charcoal adsorption led to 6.1 g/L ethanol in 48 h, with a yield of 0.30 g/g and a productivity of 0.13 g L^?1 h^?1. The detoxification by adsorption into ion-exchange resins, in turn, provided 7.5 g/L ethanol in 48 h, with a yield of 0.30 g/g and a productivity of 0.16 g L^?1 h^?1.     

Ammonium hydroxide detoxification of spruce acid hydrolysates

When dilute-acid hydrolysates from spruce are fermented to produce ethanol, detoxification is required to make the hydrolysates fermentable at reasonable rates. Treatment with alkali, usually by overliming, is one of the most efficient approaches. Several nutrients, such as ammonium and phosphate, are added to the hydrolysates prior to fermentation. We investigated the use of NH₄OH for simultaneous detoxification and addition of nitrogen source. Treatment with NH₄OH compared favorably with Ca(OH)₂, Mg(OH)₂, Ba(OH)₂, and NaOH to improve fermentability using Saccharomyces cerevisiae. Analysis of monosaccharides, furan aldehydes, phenols, and aliphatic acids was performed after the different treatments. The NH₄OH treatments, performed at pH 10.0, resulted in a substantial decrease in the concentrations of furfural and hydroxymethylfurfural. Under the conditions studied, NH₄OH treatments gave better results than Ca(OH)₂ treatments. The addition of an extra nitrogen source in the form of NH₄Cl at pH 5.5 did not result in any improvement in fermentability that was comparable to NH₄OH treatments at alkaline conditions. The addition of CaCl₂ or NH₄Cl at pH 5.5 after treatment with NH₄OH or Ca(OH)₂ resulted in poorer fermentability, and the negative effects were attributed to salt stress. The results strongly suggest that the highly positive effects of NH₄OH treatments are owing to chemical conversions rather than stimulation of the yeast cells by ammonium ions during the fermentation.     

The Influence of Different Strategies for the Saccharification of the Banana Plant Pseudostem and the Detoxification of Concentrated Broth on Bioethanol Production

Pseudostem of the Musa cavendishii banana plant was submitted to chemical pretreatments with acid (H₂SO₄ 2%, 120 °C, 15 min) and with alkali (NaOH 3%, 120 °C, 15 min), saccharified by commercial enzymes Novozymes® (Cellic CTec2 and HTec2). The influences of the pretreatments on the degradation of the lignin, cellulose and hemicellulose, porosity of the surface, particle crystallinity, and yield in reducing sugars after saccharification (Y _RS), were established. Different concentrations of biomass (70 and 100 g/L in dry matter (dm)), with different physical differences (dry granulated, crushed wet bagasse, and whole pseudostem), were used. The broth with the highest Y _RS among the different strategies tested was evaporated until the concentration of reducing sugars (RS) was to the order of 100 g/L and fermented, with and without prior detoxification with active carbon. Fermentation was carried out in Erlenmeyer flasks, at 30 °C, initial pH 5.0, and 120 rpm. In comparison to the biomass without chemical pretreatment and to the biomass pretreated with NaOH, the acid pretreatment of 70 g/L of dry granulated biomass enabled greater digestion of hemicellulose, lower index of cellulose crystallinity, and higher Y _RS (45.8 ± 0.7%). The RS increase in fermentation broth to 100 g/L, with posterior detoxification, presented higher productivity ethanol (Q _P = 1.44 ± 0.02 g/L/h) with ethanol yield (Y _P/RS) of 0.41 ± 0.02 g/g. The value of Q _P was to the order of 75% higher than Q _P obtained with the same broth without prior detoxification.