Acetone-butanol-ethanol Productivity Research Articles

Increase Butanol Production from Corn Straw by Mineral Compounds Supplementation

In this study, two types of fermentation methods: SSF and consolidation SHF/SSF were used for production of acetone-butanol-ethanol (ABE) from corn straw as a feedstock. Clostridium acetobutylicum DSM1731 was used as the fermenting organism. Corn straw was thermochemically pretreated and then hydrolyzed using three types of enzymes. The impact has been investigated on the effect of mineral compounds supplementation ((NH4)2SO4, MgSO4, (NH4)3PO4) on ABE productivity and butanol content. From the SSF, where mineral salts were supplemented into the fermentation medium, it was found that the maximum ABE and butanol concentrations were 28.35 g/L and 24.03 g/L, respectively, corresponding to a productivities of 0.295 g/L/h (ABE) and 0.250 g/L/h (butanol). In the consolidation SHF/SSF method with mineral compounds supplementation, the maximum ABE and butanol concentrations were 31.35 g/L and 28.64 g/L, respectively, corresponding to productivities of 0.327 g/L/h (ABE) and 0.298 g/L/h (butanol). Compared to control samples, mineral salts supplementation had a positive effect on cellular metabolic activities, leading to an earlier initiation of the solventogenesis stage. In supplemented samples, an increase in the rate of ABE fermentation by Clostridium was observed.

Reduction wastewater discharge in second-generation acetone-butanol-ethanol (ABE) fermentation process by adsorptive removal of organic acids toward the broth recycling system

The treatment of high chemical oxygen demand (COD) organic wastewater is one of the major technical bottlenecks for the industrialization of second-generation biobutanol production. An effective strategy to decrease the wastewater discharge in biobutanol fermentation process is broth recycling (BR). Nevertheless, the conventional BR process suffered from server organic-acid by-products inhibition, causing low butanol yield. In this study, to solve the barrier, active carbon (AC) adsorption system was hybrid with the acetone-butanol-ethanol (ABE) fermentation and ex-situ product separation (ESPR) units. After fermentation and pervaporation, organic acids that remaining in the ABE-separated broth were partially adsorbed onto AC so that improve the continuity and efficiency of the BR process. The physicochemical characterizations of different types of commercial ACs and the organic acids adsorption efficiency was evaluated by analyzing the static and dynamic adsorptions kinetics. When adopting the DD-type AC (code C299105), the better adsorbent for organic acids removal, 87.50% of fermentative wastewater can be saved whilst the ABE concentrations were also kept constantly at 15.22 ± 0.45 g L−1 in the following cycles of fermentation, and the ABE productivity was almost no changed (0.21 ± 0.01 g L−1 h−1) after 3 cycles of operation. Therefore, the AC assisted ESPR process is an attractive method for ABE production with low wastewater discharge.

Enhancing Biobutanol Production from biomass willow by pre-removal of water extracts or bark

Aiming to understand the importance of debarking on the controlled utilization of phenolic-rich willow biomass, biobutanol was produced from it by using Clostridium acetobutylicum. Acid-catalysed steam explosion and enzymatic hydrolysis (EH) were investigated before the acetone-butanol-ethanol (ABE) fermentation. The hydrolysable sugar yield and ABE fermentation efficiency were found to decline progressively from willow wood (WW) to HWE WB (hot water extracted willow biomass), WB (willow biomass) and the WW + HWE (willow wood plus the artificial willow bark water extracts), indicating that the pre-removal of water extracts or the bark can significantly improve ABE yield. Notably, the ABE productivity of WW achieved 12.7 g/L at the solvent yield of 31%, and the butanol concentration (i.e. 8.5 g/L) generated by WW is relatively high among the reported lignocellulosic-derived biomass. Additionally, it is hypothesized that under acidic conditions and high temperatures the fructose present in willow water extracts form hydroxymethylfurfural during steam explosion, which then spontaneously condenses with phenolic substances of willow bark to form a solid furanic precipitate. The formed furanic precipitates play inhibitory role in the enzymatic hydrolysis and are thereby deleterious to the ABE fermentation.

Fluorinated PDMS membrane with anti-biofouling property for in-situ biobutanol recovery from fermentation-pervaporation coupled process

Hydrophobic pervaporation membranes such as polydimethylsiloxane (PDMS) have shown great potential for biofuels recovery from fermentation process, which however face the challenge of biofouling issue. In this work, a new kind of anti-biofouling PDMS membrane was developed by creating an ultra-low energy surface via a facile crosslinking reaction between fluorosilane and PDMS. The chemical properties and wettability of the membrane surface were characterized by IR, XPS and contact angle measurements, in which the effect of chemical groups on the surface free energy was studied. The performance of PDMS membranes were evaluated in a typical acetone-butanol-ethanol (ABE) fermentation-pervaporation coupled process. The results demonstrated that the introduction of fluoroalkyl groups highly reduced the surface energy of PDMS membrane, thereby achieving excellent hydrophobicity and lipophobicity at the same time, and successfully alleviating microbial adhesion onto the membrane. As a result, the fluorinated PDMS membrane exhibited excellent anti-biofouling property, as well as much higher stabilized total flux (0.74 vs 0.36 kg/m2h) and ABE separation factor (21.8 vs 7.1) than the pristine PDMS membrane as coupling fed-batch fermentation for 140 h. In addition, a significant enhancement in ABE productivity (e.g., 51% higher than batch fermentation) was obtained in the fluorinated PDMS membrane coupled fed-batch fermentation process.

Biobutanol production from sugarcane straw: Defining optimal biomass loading for improved ABE fermentation

Key objective of this work was to evaluate the use of cellulosic fraction from sugarcane straw pretreated by liquid hot water (LHW) for butanol production via acetone-butanol-ethanol (ABE) fermentation. Separated hydrolysis and fermentation (SHF), and pre-saccharification and simultaneous saccharification and fermentation (PSSF) were investigated at 10 and 15 % w/v biomass loading. For 15 % w/v, the synergistic effect of weak acids and phenolic compounds made the sugarcane straw hydrolysate poorly fermentable. The 10 % w/v solid load was more favorable (∼ 4-fold higher) in both SHF and PSSF strategies with respect to the ABE production, without including a detoxification step. However, PSSF achieved higher ABE titer (10.5 g/L – SHF; 13.5 g/L – PSSF) and productivity (0.09 g/(L.h) – SHF; 0.14 g/(L.h) – PSSF) when compared with SHF. Using best condition (PSSF at 10 % w/v), it would be possible to estimate a yield of 169 L ABE per ton pretreated sugarcane straw (or 84.5 L ABE per ton of raw sugarcane straw), containing 65 L acetone, 95 L butanol, and 9 L ethanol. This result represents a process efficiency of 28 %, based on carbohydrates content in raw material.

Production of acetone–butanol–ethanol (ABE) from concentrated yellow top presscake using Clostridium beijerinckii P260

AbstractBACKGROUNDButanol, a superior biofuel to ethanol, can be produced by fermentation of renewable feedstocks such as corn or molasses. Since costs of these feedstocks are high, this biofuel should be produced from economic substrates. Recent studies have identified yellow top (YT) (Physaria fendleri) as an economical feedstock which is currently used for landfill, thus causing environmental pollution. In addition, cutting edge science and technology should be used, such as application of concentrated substrates. This study used concentrated YT ranging from 80 to 150 g L−1.RESULTSAt a YT concentration of 125 g L−1, the culture produced 28.8 g L−1 acetone–butanol–ethanol (ABE) as compared with 18.68 g L−1 using glucose (control) as substrate, which is 154% of the control fermentation. The control fermentation resulted in a productivity of 0.42 g L−1 h−1, while YT resulted in a productivity of 0.70 g L−1 h−1. In YT fermentation, specific ABE productivity was 543% of that obtained in the control run.CONCLUSIONA YT concentration of 125 g L−1 is beneficial for ABE fermentation. At this concentration, ABE production level, productivity and specific productivity were greatly enhanced. Published 2019. This article is a U.S. Government work and is in the public domain in the USA.

Highly efficient continuous acetone–butanol–ethanol production from mixed sugars without carbon catabolite repression

Factors including the composition and concentration of mixed sugars, dilution rate, and cell density were examined to establish a highly efficient continuous acetone–butanol–ethanol (ABE) fermentation process using Clostridium saccharoperbutylacetonicum N1-4. During conventional continuous fermentation at a dilution rate of 0.15 h−1, the glucose/xylose mixture exhibited carbon catabolite repression (CCR) with an intensity (ICCR) of 4.18 and ABE productivity of 0.574 g L−1 h−1, while CCR was alleviated using a cellobiose/xylose mixture with 1.60 and 1.09 g L−1 h−1, respectively. Continuous fermentation with high cell density by cell recycling improved ABE productivity to 5.32 g L−1 h−1 at a dilution rate of 0.686 h−1 owing to high xylose consumption. Further optimization of mixed sugar concentration in the feeding medium induced the best performance of continuous ABE production from mixed sugar without CCR, relative to previous studies: ABE productivity, 6.09 g L−1 h−1; ABE yield, 0.214 g g−1; ICCR, 1.48.

Yellow top (Physaria fendleri) presscake: A novel substrate for butanol production and reduction in environmental pollution.

Yellow Top (Physaria fendleri) is a plant that belongs to the mustard family. This plant is used to produce seeds that are rich in hydroxy oil. After extraction of oil, the presscake is land filled. The seedcake is rich in polymeric sugars and can be used for various bioconversions. For the present case, the seedcake or presscake was hydrolyzed with dilute (0.50% [v/v]) H2 SO4 and enzymes to release sugars including glucose, xylose, galactose, arabinose, and mannose. Then, the hydrolyzate was used to produce acetone-butanol-ethanol (ABE). Using 100 gL-1 presscake (prior to pretreatment), 19.22 gL-1 of ABE was successfully produced of which butanol was the major product. In this process, an ABE productivity of 0.48 gL-1 h-1 was obtained. These results are superior to glucose fermentation to produce ABE in which an ABE productivity of 0.42 gL-1 h-1 was obtained. Use of Yellow Top to produce butanol has the following advantages: (i) it is an economic feedstock and is expected to produce butanol economically; (ii) it avoids pollution concerns when not land filled; and (iii) rate of ABE production is not inhibited when fermented this substrate. It is suggested that the potential of this feedstock be further explored by optimizing process parameters for this valuable fermentation. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 35: e2767, 2019.

High solid fed-batch butanol fermentation with simultaneous product recovery: Part II-process integration.

In these studies, liquid hot water (LHW) pretreated and enzymatically hydrolyzed Sweet Sorghum Bagasse (SSB) hydrolyzates were fermented in a fed-batch reactor. As reported in the preceding paper, the culture was not able to ferment the hydrolyzate I in a batch process due to presence of high level of toxic chemicals, in particular acetic acid released from SSB during the hydrolytic process. To be able to ferment the hydrolyzate I obtained from 250 g L-1 SSB hydrolysis, a fed-batch reactor with in situ butanol recovery was devised. The process was started with the hydrolyzate II and when good cell growth and vigorous fermentation were observed, the hydrolyzate I was slowly fed to the reactor. In this manner the culture was able to ferment all the sugars present in both the hydrolyzates to acetone butanol ethanol (ABE). In a control batch reactor in which ABE was produced from glucose, ABE productivity and yield of 0.42 g L-1 h-1 and 0.36 were obtained, respectively. In the fed-batch reactor fed with SSB hydrolyzates, these productivity and yield values were 0.44 g L-1 h-1 and 0.45, respectively. ABE yield in the integrated system was high due to utilization of acetic acid to convert to ABE. In summary we were able to utilize both the hydrolyzates obtained from LHW pretreated and enzymatically hydrolyzed SSB (250 g L-1 ) and convert them to ABE. Complete fermentation was possible due to simultaneous recovery of ABE by vacuum. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:967-972, 2018.

Kinetic modelling and simulation of batch, continuous and cell-recycling fermentations for acetone-butanol-ethanol production using Clostridium saccharoperbutylacetonicum N1-4

A kinetic model describing acetone-butanol-ethanol (ABE) production applicable to both single substrate fermentations of glucose and xylose as well as co-fermentation of the substrates has been developed. The model accounts for carbon catabolite repression as well as the inhibition of kinetic rates at high substrate concentrations (∼90 g l−1). Model parameters were obtained through kinetic fitting to previously report experimental data. The model was used to study the design and operation of a continuous ABE fermentation process (with and without recycle of biomass). For continuous operation, it was shown that multiple steady-states exist at low dilution rates. For operation with recycle of biomass, the influence of recycle rate on both biomass concentration and ABE productivity were studied. The results indicate that for a range of recycle and dilution rates, ABE productivity can increase to 16 g l−1 h−1 (10 times higher than that without biomass recycling), consistent with experimental results.

Repeated-batch fermentation by immobilization of Clostridium beijerinckii NCIMB 8052 in a fibrous bed bioreactor for ABE (acetone-butanol-ethanol) production

In this study, a fibrous bed bioreactor (FBB) system was used to produce ABE (acetone-butanol-ethanol) by immobilized cells of Clostridium beijerinckii NCIMB 8052. To obtain the maximum ABE productivity and yield and maintain the stability of a repeated-batch fermentation process in the FBB system, the optimal dilution rate (0.17 min−1) and initial glucose concentration (18 g/l) in the bioreactor were determined. When the repeated-batch fermentation was maintained at 11 cycles under the optimal conditions, an average of 4.9 g/l butanol (maximum 5.3 g/l) was achieved with an average solvent productivity of 1.0 g/l/h and a yield of 0.41 g/g (maxima of 1.1 g/l/h and 0.43 g/g, respectively). However, the solvent productivity and yield in batch fermentation of free cells were just 0.29 g/l/h and 0.36 g/g, respectively. In addition, scanning electron micrographs demonstrated that C. beijerinckii cells can be adsorbed onto a cotton towel and they exhibited a significantly different morphology compared to immobilized Clostridium acetobutylicum.

Use of Cupriavidus basilensis-aided bioabatement to enhance fermentation of acid-pretreated biomass hydrolysates by Clostridium beijerinckii.

Lignocellulose-derived microbial inhibitors (LDMICs) prevent efficient fermentation of Miscanthus giganteus (MG) hydrolysates to fuels and chemicals. To address this problem, we explored detoxification of pretreated MG biomass by Cupriavidus basilensis ATCC(®)BAA-699 prior to enzymatic saccharification. We document three key findings from our test of this strategy to alleviate LDMIC-mediated toxicity on Clostridium beijerinckii NCIMB 8052 during fermentation of MG hydrolysates. First, we demonstrate that growth of C. basilensis is possible on furfural, 5-hydroxymethyfurfural, cinnamaldehyde, 4-hydroxybenzaldehyde, syringaldehyde, vanillin, and ferulic, p-coumaric, syringic and vanillic acid, as sole carbon sources. Second, we report that C. basilensis detoxified and metabolized~98% LDMICs present in dilute acid-pretreated MG hydrolysates. Last, this bioabatement resulted in significant payoffs during acetone-butanol-ethanol (ABE) fermentation by C. beijerinckii: 70, 50 and 73% improvement in ABE concentration, yield and productivity, respectively. Together, our results show that biological detoxification of acid-pretreated MG hydrolysates prior to fermentation is feasible and beneficial.

Combined Detoxification and In-situ Product Removal by a Single Resin During Lignocellulosic Butanol Production.

Phragmites australis (an invasive plant in North America) was used as feedstock for ABE (acetone-butanol-ethanol) fermentation by Clostridium saccharobutylicum. Sulphuric acid pretreated phragmites hydrolysate (SAEH) without detoxification inhibited butanol production (0.73 g/L butanol from 30 g/L sugars). The treatment of SAEH with resin L-493 prior the fermentation resulted in no inhibitory effects and an ABE titer of 14.44 g/L, including 5.49 g/L butanol was obtained, corresponding to an ABE yield and productivity of 0.49 g/g and 0.60 g/L/h, respectively. Dual functionality of the resin was realized by also using it as an in-situ product removal agent. Integrating in-situ product removal allowed for the use of high substrate concentrations without the typical product inhibition. Resin-detoxified SAEH was supplemented with neat glucose and an effective ABE titer of 33 g/L (including 13.7 g/L acetone, 16.4 g/L butanol and 1.9 g/L ethanol) was achieved with resin-based in-situ product removal, corresponding to an ABE yield and productivity of 0.41 g/g and 0.69 g/L/h, respectively. Both detoxification of the substrate and the products was achieved by the same resin, which was added prior the fermentation. Integrating hydrolysate detoxification and in-situ butanol removal in a batch process through single resin can potentially simplify cellulosic butanol production.

Cellulosic Butanol (ABE) Biofuel Production from Sweet Sorghum Bagasse (SSB): Impact of Hot Water Pretreatment and Solid Loadings on Fermentation Employing Clostridium beijerinckii P260

A novel butanol fermentation process was developed in which sweet sorghum bagasse (SSB) was pretreated using liquid hot water (LHW) pretreatment technique followed by enzymatic hydrolysis and butanol (acetone butanol ethanol (ABE)) fermentation. A pretreatment temperature of 200 °C resulted in the generation of a hydrolyzate that inhibited butanol fermentation. When SSB pretreatment temperature was decreased to 190 °C (0-min holding time), the hydrolyzate was successfully fermented without inhibition and an ABE productivity of 0.51 g L−1 h−1 was achieved which is comparable to the 0.49 g L−1 h−1 observed in the control fermentation where glucose was used as a feedstock. These results are based on the use of 86 g L−1 SSB solid loadings in the pretreatment reactors. We were also able to increase SSB solid loadings from 120 to 200 g L−1 in the pretreatment step (190 °C) followed by hydrolysis and butanol fermentation. As pretreatment solid loadings increased, ABE yield remained in the range of 0.38–0.46. In these studies, a maximum ABE concentration of 16.88 g L−1 was achieved. Using the LHW pretreatment technique, 88.40–96.00 % of polymeric sugars (cellulose + hemicellulose) were released in the SSB hydrolyzate. The LHW pretreatment technique does not require chemical additions and is environmentally friendly, and the hydrolyzate can be used successfully for butanol fermentation.

Periodic peristalsis increasing acetone–butanol–ethanol productivity during simultaneous saccharification and fermentation of steam-exploded corn straw

The acetone-butanol-ethanol (ABE) fermentation of lignocellulose at high solids content has recently attracted extensive attention. However, the productivity of high solids ABE fermentation of lignocellulose is typically low in traditional processes due to the lack of efficient intensifying methods. In the present study, periodic peristalsis, a novel intensifying method, was applied to improve ABE production by the simultaneous saccharification and fermentation (SSF) of steam-exploded corn straw using Clostridium acetobutylicum ATCC824. The ABE concentration and the ABE productivity of SSF at a solids content of 17.5% (w/w) with periodic peristalsis were 17.1g/L and 0.20g/(Lh), respectively, which were higher than those obtained under static conditions (15.2g/L and 0.14g/(Lh)). The initial sugar conversion rate over the first 12h with periodic peristalsis was 4.67g/(Lh) at 10 FPU/g cellulase dosage and 15% (w/w) solids content, an increase of 49.7% compared with the static conditions. With periodic peristalsis, the period of batch fermentation was shortened from 108h to 84h. The optimal operating regime was a low frequency (6h-1) of periodic peristalsis in the acid-production phase (0-48h) of SSF. Therefore, periodic peristalsis should be an effective intensifying method to increase the productivity of ABE fermentation at high solids content.

Performance of fed-batch acetone–butanol–ethanol (ABE) fermentation coupled with the integrated in situ extraction-gas stripping process and the fractional condensation

In this study, fed-batch acetone–butanol–ethanol (ABE) fermentation was coupled with the integrated in situ extraction-gas stripping process. The total glucose consumptions were 255 and 310 g/L at the gas flow rates of 0.5 and 1.0 liter per minute (lpm), respectively. The ABE productivity and yield were 0.65 g/L/h and 0.43 g-solvent/g-glucose at the gas flow rates of 0.5 lpm. When the gas flow rates increased from 0.5 to 1.0 lpm, the ABE productivity and yield became 0.69 g/L/h and 0.48 g-solvent/g-glucose, respectively. The fractional condensation was operated by using two different cold traps where temperatures for the first and second one were 2 and −196°C, respectively. It was found that 71–81 and 64–73% of total stripped water was condensed in the 2 °C cold trap at gas flow rates of 0.5 and 1.0 lpm, respectively. Therefore, high ABE concentrations of 360–460 g/L were found in the second cold trap. The overall separation factor for butanol was calculated to be up to 34 where the raffinate solution is the fermentation broth and the extract solution is the condensate in the −196 °C cold trap.

Enhanced acetone-butanol production from sugarcane juice by immobilized Clostridium acetobutylicum (ATCC 824) on thin-shell silk cocoons

To promote its performance during acetone-butanol-ethanol (ABE) fermentation, Clostridium acetobutylicum (ATCC 824) was immobilized on a thin-shell silk cocoon (TSC). As a residual from the silk industry, TSC offers a cheap, biocompatible support material. The adsorbed C. acetobutylicum cells digested the TSCs into amino acids as a nitrogen source. It was shown that TSC might promote the phase shift to acetone in the ABE fermentation. At an initial reducing sugar concentration of 90 g/L, the ABE productivity of the immobilized cell culture on TSC (IC-TSC) in batch fermentation was 0.18 g/L/h, and the solvent mixture comprised 6.1 g/L acetone, 15.9 g/L butanol, and 1.9 g/L ethanol. Repeated 4-cycle batch fermentation using IC-TSC significantly improved the ABE productivity. After 48 h of cyclic fermentation, the maximum ABE productivity was 0.43 g/L/h with acetone, butanol and ethanol concentrations of 6.6, 12.9, and 1.1 g/L, respectively.

Acetone–butanol–ethanol (ABE) fermentation integrated with simplified gas stripping using sweet sorghum bagasse as immobilized carrier

In this study, the influence of sweet sorghum bagasse (SSB) as immobilized carrier on acetone–butanol–ethanol (ABE) fermentation integrated with gas stripping was investigated. During the integrated process, the immobilized bioreactor was also treated as the spinner flask for gas stripping. It appeared that the homogenization of the fermentation broth and the efficiency of solvents separation were enhanced. With the immobilized bioreactor treated as the spinner flask, fed-batch fermentation that integrated with intermittent and that integrated with continuous gas stripping were investigated, respectively. As a result, 155.7–255.6g/L of ABE solvent was achieved in the condensate with 0.38±0.06g/L/h of productivity in the intermittent gas stripping scenario, while 180±25g/L of ABE in the condensate with productivity of ∼1.15g/L/h were achieved in the continuous gas stripping integrated scenario. The simplified integrated process showed advantage both in ABE productivity and concentration compared with other reports.

Block copolymer pervaporation membrane for in situ product removal during acetone–butanol–ethanol fermentation

We address two major challenges facing commercialization of acetone–butanol–ethanol (ABE) fermentation: product inhibition and low productivity. We studied a polystyrene-b-polydimethylsiloxane-b-polystyrene (SDS) triblock copolymer membrane for selective removal of butanol from aqueous solutions by pervaporation. The SDS membrane exhibited higher permeabilities than a commercially available cross-linked polydimethylsiloxane (PDMS) membrane. Both types of pervaporation membrane were also used for in situ product removal of ABE biofuels in Clostridium acetobutylicum fermentations operated in a semi-continuous mode. Membrane performance and its effect on the fermentation process were assessed by measuring flux, OD600 and concentrations of different components in the fermenter as a function of time. Volumetric ABE productivity increased from 0.45g/(Lh) in simple batch fermentation to 0.66g/(Lh) in the case of pervaporative-fermentation with the PDMS membrane. A further increase in productivity to 0.94g/(Lh) was obtained in the case of pervaporative-fermentation with the SDS membrane. Overall, total ABE production improved by a factor of three, viable fermentation time increased by a factor of two, and cell density increased by a factor of 2.5 upon applying SDS membrane pervaporation, relative to the batch process.

Feasibility of acetone–butanol–ethanol fermentation from eucalyptus hydrolysate without nutrients supplementation

The economic feasibility of acetone–butanol–ethanol (ABE) fermentation is greatly affected by the type of raw material used. The easy availability of eucalyptus from marginal environments is an alternative feedstock for use as raw material to reduce the production cost. In this study, hydrolyzed eucalyptus was used for ABE production without any nutrients supplementation. Increasing the solid concentration in the eucalyptus slurry from 6.7% (w-dry matter/v) to 25% led to an increase in the initial glucose concentration from 33.7g/L to 86.7g/L after enzymatic hydrolysis. Dosed cellulases not only hydrolyzed cellulose but also supplied nitrogen source for ABE producing strain. However, ABE production from the obtained hydrolysate decreased when the solid concentration was increased to more than 10%. The maximum ABE of 12.3g/L was obtained at 10% solid concentration, with an initial glucose concentration of approximately 40g/L. In addition, the fermentation capability of eucalyptus hydrolysate was found to be improved by diluting the hydrolysate, which prevented inhibition by substrate and fermentation inhibitors. Finally, ABE concentration was improved to 13.1g/L by diluting the hydrolysate from the initial solid concentration of 25% to an initial glucose concentration of 45g/L, which resulted in ABE productivity of 0.109g/L/h and ABE yield of 0.413g/g. Thus, the high ABE production from eucalyptus makes it a potential feedstock for biofuel production.