Separate Hydrolysis And Fermentation Research Articles

Bioconversion of wastewater-derived duckweed to lactic acid through fed-batch fermentation at high-biomass loading

After being collected from the wastewater treatment system, duckweed biomass which is rich in starch and protein has the potential to be converted to valuable chemicals. This study aimed to establish a fermentation process for bioconversion of duckweed biomass derived from wastewater treatment to lactic acid (LA) by Lactobacillus casei. The Lactobacillus casei CICC 23184 showed the best LA production ability in duckweed-based medium among five strains. Simultaneous saccharification and fermentation (SSF) and separated hydrolysis and fermentation (SHF) were conducted, and the SSF had better performance even with lower enzyme dosage. No extra nitrogen source needed supplying into duckweed-based media. In batch fermentation, biomass loading of 220 g kg−1 was optimal with LA concentration of 72.51 ± 2.81 g kg−1 and yield of 0.35 ± 0.01 g g−1dry biomass. The highest LA concentration (100.36 ± 3.31 g kg−1), yield (0.38 ± 0.01 g g−1dry biomass), and productivity (2.09 ± 0.07 g kg−1 h−1) were obtained through fed-batch SSF at a final biomass loading of 260 g kg−1. This study demonstrated that it is feasible to utilize duckweed biomass as feedstock to produce LA through fermentation, and a fed-batch SSF at high-biomass loading was successfully established. This study provides a novel strategy for sustainable recycling of duckweed biomass derived from wastewater treatment.

Sequential pretreatment of sugarcane bagasse by alkali and organosolv for improved delignification and cellulose saccharification by chimera and cellobiohydrolase for bioethanol production.

The online version contains supplementary material available at 10.1007/s13205-020-02600-y.

Sustainable Second-Generation Bioethanol Production from Enzymatically Hydrolyzed Domestic Food Waste Using Pichia anomala as Biocatalyst

In the current study, a domestic food waste containing more than 50% of carbohydrates was assessed as feedstock to produce second-generation bioethanol. Aiming to the maximum exploitation of the carbohydrate fraction of the waste, its hydrolysis via cellulolytic and amylolytic enzymatic blends was investigated and the saccharification efficiency was assessed in each case. Fermentation experiments were performed using the non-conventional yeast Pichia anomala (Wickerhamomyces anomalus) under both separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) modes to evaluate the conversion efficiencies and ethanol yields for different enzymatic loadings. It was shown that the fermentation efficiency of the yeast was not affected by the fermentation mode and was high for all handlings, reaching 83%, whereas the enzymatic blend containing the highest amount of both cellulolytic and amylolytic enzymes led to almost complete liquefaction of the waste, resulting also in ethanol yields reaching 141.06 ± 6.81 g ethanol/kg waste (0.40 ± 0.03 g ethanol/g consumed carbohydrates). In the sequel, a scale-up fermentation experiment was performed with the highest loading of enzymes in SHF mode, from which the maximum specific growth rate, μmax, and the biomass yield, Yx/s, of the yeast from the hydrolyzed waste were estimated. The ethanol yields that were achieved were similar to those of the respective small scale experiments reaching 138.67 ± 5.69 g ethanol/kg waste (0.40 ± 0.01 g ethanol/g consumed carbohydrates).

A biorefinery approach for the production of bioethanol from alkaline-pretreated, enzymatically hydrolyzed Nicotiana tabacum stalks as feedstock for the bio-based industry

In this study, an attempt was made to investigate bioethanol production using low-cost feedstock, namely, tobacco wastes obtained after the leaves harvesting. Tobacco stalks, an abundant biomass source of the leftover agricultural crop field, are a promising feedstock for bioethanol production. Traditional Thai tobacco (Nicotiana tabacum L.) is known as non-Virginia type tobacco stalks and was used as biomass feedstock for ethanol production by separate hydrolysis and fermentation (SHF) with a computerized fermenter. Tobacco stalks were efficiently hydrolyzed after a mild physical-chemical pretreatment. The economically cheapest alkaline chemical (2% CaO) was used for pretreatment. The robust yeast Saccharomyces cerevisiae was utilized, and it is suitable for industrial ethanol production. These data suggest that tobacco stalks are potential candidates for ethanol production from physical alkali-pretreated biomass with enzymatic hydrolysis on the SHF system.

Expeditious production of concentrated glucose-rich hydrolysate from sugarcane bagasse and its fermentation to lactic acid with high productivity

Sugarcane bagasse (SCB) is anticipated to emerge as a potential threat to waste management in India on account of cheap surplus energy options and lower incentives through its co-generation. Through biotechnological intervention, the efficient utilization of SCB is seen as an opportunity. The present study aimed towards expeditious production of concentrated glucose-rich hydrolysate from SCB. Alkali pretreated biomass was chosen for hydrolysis with a new generation cellulase cocktail, Cellic CTec2 dosed at 25 mg g−1 glucan content. A two-step (9% + 9%) substrate feeding strategy was adopted with a gap of an hour, and saccharification was terminated in three different ways. Irrespective of the methods employed for termination, ∼84.5% cellulose was hydrolyzed releasing ≥100 g L−1 glucose from 18% biomass. Direct use of glucose-rich filtrates yielded 69.2 ± 2.5 g L−1 of L (+) lactic acid using thermophilic Bacillus coagulans NCIM 5648. The best-attained glucose and lactic acid productivities during separate hydrolysis and fermentation (SHF) in the present study were 5.27 and 2.88 g L−1 h−1, respectively. A green and sustainable process is demonstrated for the production of industrially relevant sugars from SCB at high productivity and its valorization to bio-based lactic acid.

Designing Efficient Processes for Sustainable Bioethanol and Bio-Hydrogen Production from Grass Lawn Waste.

The effect of thermal, acid and alkali pretreatment methods on biological hydrogen (BHP) and bioethanol production (BP) from grass lawn (GL) waste was investigated, under different process schemes. BHP from the whole pretreatment slurry of GL was performed through mixed microbial cultures in simultaneous saccharification and fermentation (SSF) mode, while BP was carried out through the C5yeast Pichia stipitis, in SSF mode. From these experiments, the best pretreatment conditions were determined and the efficiencies for each process were assessed and compared, when using either the whole pretreatment slurry or the separated fractions (solid and liquid), the separate hydrolysis and fermentation (SHF) or SSF mode, and especially for BP, the use of other yeasts such as Pachysolen tannophilus or Saccharomyces cerevisiae. The experimental results showed that pretreatment with 10 gH2SO4/100 g total solids (TS) was the optimum for both BHP and BP. Separation of solid and liquid pretreated fractions led to the highest BHP (270.1 mL H2/g TS, corresponding to 3.4 MJ/kg TS) and also BP (108.8 mg ethanol/g TS, corresponding to 2.9 MJ/kg TS) yields. The latter was achieved by using P. stipitis for the fermentation of the hydrolysate and S. serevisiae for the solid fraction fermentation, at SSF.

Production of xylose, xylulose, xylitol, and bioethanol from waste bamboo using hydrogen peroxicde-acetic acid pretreatment

Bioethanol is a typical product of biorefineries, and an alternative to fossil fuels, which increase greenhouse gas emission levels. However, high production costs hinder the widespread adoption of bioethanol refineries. Co-production of bioethanol and other value added by-products from waste biomass is an effective strategy to improve the cost competitiveness of bioethanol production. Disruption of the lignin structure in waste bamboo via hydrogen peroxide-acetic acid (HPAC) pretreatment improved the efficiency of the hydrolysis more than six times compared to hydrolysis without pretreatment. HPAC-pretreatment yielded no significant difference between separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) processes in terms of the productivity of ethanol fermentation with optimized enzyme doses In contrast, the productivity of xylose was higher with SHF rather than SSF. Both products were successfully separated using a polydimethylsiloxane/polyetherimide (PDMS/PEI) hollow-fiber membrane. Co-production of xylose and bioethanol improved cost-competitiveness by simultaneous conversion processes for the co-production of xylulose and xylitol as value added byproducts.

The immobilization of yeast for fermentation of macroalgae Rhizoclonium sp. for efficient conversion into bioethanol

Macroalgae are considered to be one of the rich lignocellulosic biomass materials. Aquatic biomass has gained more attention to biofuels generation in recent years due to its renewable, abundant, and environmentally friendly aspects. Macroalgae are photosynthetic organisms that are found in both marine and freshwater environments. These are considered as a third-generation feedstock for the production of biofuels since they have the ability to synthesize a high amount of lipids, proteins, and carbohydrates. This research study aimed to evaluate the potential of bioethanol production from macroalgae (Rhizoclonium sp.) biomass. The fermentation process was applied in the research by two-way separate hydrolysis and fermentation (SHF). Algae biomass undergoes a pretreatment process to release necessary sugars for yeast digestion. The fermentation process was carried at 30 to 35 °C in the incubator. Finally, the percentage of ethanol was estimated by the ebulliometer. Fermentation was enhanced by immobilization of yeast, which showed the highest concentration of ethanol (65.43 ± 18.13 g/l) after 96 h of fermentation and can be reused for several times for fermentation. Moreover, these study results confirmed that freshwater macroalgae biomass is a suitable and susceptible raw material for bioethanol production.

Feasibility assessment of the production of bioethanol from lignocellulosic biomass pretreated with acid mine drainage (AMD)

A techno-economic evaluation of a lignocellulosic bioethanol facility that uses acid mine drainage for the pre-treatment of weeping love grass (Eragrostis curvula) was performed. Both separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) reactor configurations were evaluated. Results were compared to an evaluation of the same process with biomass pre-treated with dilute H2SO4. Capital and operating costs were estimated and a simple economic evaluation was conducted. It was found that all scenarios made a loss except for biomass pre-treated with H2SO4 in the SHF reactor configuration, although the high capital cost resulted in a payback period of 80.7 years, which is unfeasible. SHF was found to produce more ethanol at a lower capital cost than SSF, indicating that it is more economically feasible. Incorporating the remediation of AMD into a simultaneous process could help improve process economics. It is thus recommended that a techno-economic evaluation be conducted on a process that produces bioethanol through SHF and simultaneously remediates AMD.

Evaluation of Napier Grass for Bioethanol Production through a Fermentation Process

Ethanol is one of the widely used liquid biofuels in the world. The move from sugar-based production into the second-generation, lignocellulosic-based production has been of interest due to an abundance of these non-edible raw materials. This study interested in the use of Napier grass (Pennisetum purpureum Schumach), a common fodder in tropical regions and is considered an energy crop, for ethanol production. In this study, we aim to evaluate the ethanol production potential from the grass and to suggest a production process based on the results obtained from the study. Pretreatments of the grass by alkali, dilute acid, and their combination prepared the grass for further hydrolysis by commercial cellulase (Cellic® CTec2). Separate hydrolysis and fermentation (SHF), and simultaneous saccharification and fermentation (SSF) techniques were investigated in ethanol production using Saccharomyces cerevisiae and Scheffersomyces shehatae, a xylose-fermenting yeast. Pretreating 15% w/v Napier grass with 1.99 M NaOH at 95.7 °C for 116 min was the best condition to prepare the grass for further enzymatic hydrolysis using the enzyme dosage of 40 Filter Paper Unit (FPU)/g for 117 h. Fermentation of enzymatic hydrolysate by S. cerevisiae via SHF resulted in the best ethanol production of 187.4 g/kg of Napier grass at 44.7 g/L ethanol concentration. The results indicated that Napier grass is a promising lignocellulosic raw material that could serve a fermentation with high ethanol concentration.

Enhanced Bioethanol Fermentation by Sonication Using Three Yeasts Species and Kariba Weed (Salvinia molesta) as Biomass Collected from Lake Victoria, Uganda.

Kariba weed (Salvinia molesta) was used as biomass feedstock for ethanol production by separate hydrolysis and fermentation (SHF). Monosaccharides from Kariba weed hydrolysate were produced using thermal acid hydrolysis, sonication, and enzymatic saccharification. The optimal conditions for thermal acid hydrolysis of 12% (w/v) Kariba weed slurry were evaluated as 200mM HNO3 at 121°C for 60min yielding 10.2g/L monosaccharides. Sonication for 45min before enzymatic saccharification yielded more monosaccharides to 18.7g/L. Enzymatic saccharification with 16U/mL Cellic CTec2 produced 35.4g/L monosaccharides. Fermentation was performed using Saccharomyces cerevisiae, Kluyveromyces marxianus, or Pichia stipitis with sonicated Kariba weed hydrolysate. The control fermentations were carried out using Kariba weed hydrolysate without sonication. The improvement of ethanol production from sonicated Kariba weed hydrolysate using P. stipitis produced 15.9g/L ethanol with ethanol yield coefficient YEtOH = 0.45, K. marxianus produced 14.7g/L ethanol with YEtOH = 0.41. S. cerevisiae produced the lowest yield of 13.2g/L ethanol with YEtOH = 0.37 as it utilized only glucose not xylose. Sonication of Kariba weed was essential in the ethanol production to enhance the productivity of monosaccharides. P. stipitis was determined as the best yeast species using hydrolysates with the mixture of glucose and xylose to produce ethanol.

Development of a green liquor dregs pretreatment for enhanced glucose recovery from corn cobs and kinetic assessment on various bioethanol fermentation types

This study optimized a novel pretreatment of corn cob wastes (CCW) using green liquor dregs (GLD), a waste product from the chemical kraft pulping industry. Subsequently, the microbial growth and ethanol production kinetics of different bioprocess types were comparatively evaluated using the logistic and modified Gompertz models respectively. The optimized GLD pretreatment conditions released a maximum glucose yield of 0.42 g/g. Separate hydrolysis and fermentation (SHF), simultaneous saccharification and fermentation (SSF) and SSF with pre hydrolysis (PSSF) processes were assessed and gave comparable kinetic data. The SHF and PSSF processes displayed slightly higher microbial and bioethanol kinetic coefficients compared to the SSF system. Implications from this study provide major insights for reducing energy, time and costs incurred with lignocellulosic substrate pretreatment, bioethanol process design and scale up. Additionally, the study demonstrates a possible route for beneficiation of waste material such as GLD.

Effect of residual extractable lignin on acetone\u2013butanol\u2013ethanol production in SHF and SSF processes

BackgroundLignin plays an important role in biochemical conversion of biomass to biofuels. A significant amount of lignin is precipitated on the surface of pretreated substrates after organosolv pretreatment. The effect of this residual lignin on enzymatic hydrolysis has been well understood, however, their effect on subsequent ABE fermentation is still unknown.ResultsTo determine the effect of residual extractable lignin on acetone–butanol–ethanol (ABE) fermentation in separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) processes, we compared ABE production from ethanol-washed and unwashed substrates. The ethanol organosolv pretreated loblolly pine (OPLP) was used as the substrate. It was observed that butanol production from OPLP-UW (unwashed) and OPLP-W (washed) reached 8.16 and 1.69 g/L, respectively, in SHF. The results showed that ABE production in SHF from OPLP-UW prevents an “acid crash” as compared the OPLP-W. In SSF process, the “acid crash” occurred for both OPLP-W and OPLP-UW. The inhibitory extractable lignin intensified the “acid crash” for OPLP-UW and resulted in less ABE production than OPLP-W. The addition of detoxified prehydrolysates in SSF processes shortened the fermentation time and could potentially prevent the “acid crash”.ConclusionsThe results suggested that the residual extractable lignin in high sugar concentration could help ABE production by lowering the metabolic rate and preventing “acid crash” in SHF processes. However, it became unfavorable in SSF due to its inhibition of both enzymatic hydrolysis and ABE fermentation with low initial sugar concentration. It is essential to remove extractable lignin of substrates for ABE production in SSF processes. Also, a higher initial sugar concentration is needed to prevent the “acid crash” in SSF processes.

Bioconversion of hazelnut shell using near critical water pretreatment for second generation biofuel production

The global energy deficiency and depletion of fossil fuels have raised concerns leading to a wide scale examination of alternative and renewable energy sources. Lignocellulosic biomass that is one of the renewable energy sources has major potential in the world and it has a wide variety of sources including agricultural residues such as cotton stalk, corn stover, wheat straw, etc. Including over 65% cellulose and hemicelluloses content, these materials can be hydrolyzed into monomeric sugars and then can be converted into biofuels and other industrial products.The main objective of this study is bioethanol production with bioconversion of lignocellulosic biomass, namely hazelnut shell. In order to efficiently utilize this raw material for ethanol production by degrading the lignocellulosic structure, an effective pretreatment is required. LHW, a near critical water pretreatment method, is chosen for this particular research due to its unique environmental and economic properties. The experiment design was prepared with Response Surface Estimation Method (RSM) by Design Expert software. The experiment parameters were selected as temperature (100–200 °C), pressure (80–200 bar) and flow rate (2–8 ml/min). The optimum condition (OC) for the process was determined as 138 °C, 2 ml/min and 200 bar according to the Dinitrosaliclic acid (DNS) method. Additionally, in order to achieve maximum ethanol concentration, the condition producing maximum reducing sugar content is determined. Separated hydrolysis and fermentation (SHF) process was used for bioethanol production. Enzymatic hydrolysis was conducted with a part of solid residue obtained from the maximum ethanol condition (MEC) for bioethanol production. MEC is 200 °C, 2 ml/min and 200 bar. Under MEC, at the end of the fermentation process maximum ethanol yield was 44.89% with 0.5 g of solid loading.The main purpose of the study is to determine the effects of different solid loading rates in the enzymatic hydrolysis stage of SHF process to ethanol production as a result of fermentation. There are several pretreatment methods for this process. It is concluded that the superior qualities of LHW pretreatment in means of environmental friendliness, non-toxic and non-corrosive byproducts, water usage instead of other chemical additives, degradation of lignocellulosic structure and low cost were suitable for the intended purpose of bioethanol production using hazelnut shell.

Co-generation of liquid biofuels from lignocellulose by integrated biochemical and hydrothermal liquefaction process

Different thermal stability of three major components is a challenge to efficiently liquefy lignocellulosic biomass into bio-oil because the degradation products from holocellulose can react with lignin, resulting in repolymerization reactions. In this work, a biorefinery approach of co-generation of bioethanol and bio-oil from rice straw that integrated separate hydrolysis and fermentation (SHF) and hydrothermal liquefaction (HTL) processes was proposed. SHF of dilute sulfuric acid pretreated rice straw gave a bioethanol concentration of 8.3 g/L with approximately 68% of theoretical yield. The maximum bio-oil yield 31.36 wt% via HTL of solid fermentation residues using bioethanol wastewater as the solvent was obtained under optimum conditions. Mass balance showed that 9.7 wt% bioethanol and 15.0 wt% bio-oil were produced corresponding to 56% energy recovery. Separate conversion of cellulose and lignin could be one promising way to enhance the overall energy recovery from lignocellulose to liquid biofuels.

Combined water extraction and sodium chlorite pretreated spent mushroom compost for protease production by separate hydrolysis and fermentation and simultaneous saccharification and co-fermentation

A process of simultaneous saccharification and protease production was successfully established from spent mushroom compost (SMC) created through edible fungi cultivation. The combined water extraction and sodium chlorite pretreatment significantly (p < 0.05) improved enzymatic digestibility of SMC, which led to a reducing sugar yield of 0.759 g/g that was 12 times higher than raw SMC. The water extract from SMC was recycled for simultaneous saccharification and protease production from pretreated SMC by Bacillus subtilis DES-59, which promoted the protein concentration and neutral protease activity by 21.9% and 11.6%, respectively. The simultaneous saccharification and co-fermentation (SScF) of pretreated SMC by Bacillus subtilis DES-59 produced 5518 U/mL protease, which was superior to the separate hydrolysis and fermentation (SHF) process. Fermentation residues containing Bacillus subtilis cells could be further converted into fertilizer. The closed-loop utilization of SMC was achieved using established processes, which indicates potential for application in future biorefineries.

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.

Ethanol Production from Hydrolyzed Kraft Pulp by Mono- and Co-Cultures of Yeasts: The Challenge of C6 and C5 Sugars Consumption

Second-generation bioethanol production’s main bottleneck is the need for a costly and technically difficult pretreatment due to the recalcitrance of lignocellulosic biomass (LCB). Chemical pulping can be considered as a LCB pretreatment since it removes lignin and targets hemicelluloses to some extent. Chemical pulps could be used to produce ethanol. The present study aimed to investigate the batch ethanol production from unbleached Kraft pulp of Eucalyptus globulus by separate hydrolysis and fermentation (SHF). Enzymatic hydrolysis of the pulp resulted in a glucose yield of 96.1 ± 3.6% and a xylose yield of 94.0 ± 7.1%. In an Erlenmeyer flask, fermentation of the hydrolysate using Saccharomyces cerevisiae showed better results than Scheffersomyces stipitis. At both the Erlenmeyer flask and bioreactor scale, co-cultures of S. cerevisiae and S. stipitis did not show significant improvements in the fermentation performance. The best result was provided by S. cerevisiae alone in a bioreactor, which fermented the Kraft pulp hydrolysate with an ethanol yield of 0.433 g·g−1 and a volumetric ethanol productivity of 0.733 g·L−1·h−1, and a maximum ethanol concentration of 19.24 g·L−1 was attained. Bioethanol production using the SHF of unbleached Kraft pulp of E. globulus provides a high yield and productivity.

Valorization of oil palm empty fruit bunch for bioethanol production through separate hydrolysis and fermentation (SHF) using immobilized cellulolytic enzymes

Oil palm empty fruit bunch (EFB) is a lignocellulosic waste from oil palm industry. This biomass is composed of cellulose, hemicellulose, and lignin which could be a good feedstock for second-generation bioethanol production. The cellulolytic enzyme is one of important biocatalyst for conversion cellulose into glucose that subsequently could be fermented to ethanol. However, instability of enzyme is considered as a barrier for large-scale production. Enzyme immobilization is believed can obtain the high stability of enzyme. Therefore, this study explores the immobilization of cellulolytic enzyme on mixed Ca-alginate-activated carbon beads for separate hydrolysis and fermentation (SHF) process of EFB. The mixed of 3% w/v of sodium alginate and 3% w/v of activated carbon was used in immobilized enzymes. Variation of substrate concentration (50 g/L, 100 g/L, and 150 g/L) was conducted in this study. Hydrolysis process was carried out at 50°C, pH 4.8 and 150 rpm of agitation for 96 h. Furthermore, the hydrolyzate was fermented using yeast Saccharomyces cerevisiae to produce ethanol. As results, immobilized of cellulolytic enzyme could convert cellulose into glucose in hydrolysis. The highest glucose yield of 75.48% was provided from 150 g/L of substrate loading concentration. Furthermore, ethanol yield of 78.95% could be provided in fermentation process of 150 g/L of EFB. These results indicate the use of immobilized enzymes could be applied in hydrolysis for bioethanol production.

Enhanced production of cellulosic butanol by simultaneous co-saccharification and fermentation of water-soluble cellulose oligomers obtained by chemical hydrolysis

Butanol attracted interests as a drop-in biofuel obtainable from cellulosic wastes. However, the process typically used for cellulose bioconversion, i.e., separate hydrolysis and fermentation (SHF) of pretreated cellulose (Process I), is insufficient for energy-efficient production of fuel grade butanol due to the limited obtainable butanol titer. Recently, post-hydrolysis of chemically formed water-soluble cellulose oligomers was suggested for acetone-butanol-ethanol (ABE) production in SHF mode of operation (Process II). In this study, it was found that simultaneous saccharification and fermentation of the soluble oligomers (oligomeric-SSF) (Process III) and simultaneous co-saccharification and fermentation (SCSF) of soluble oligomers along with regenerated cellulose (Process IV) are promising alternatives for upgrading the titer and yield of cellulosic butanol production by Clostridium acetobutylicum. In Process III, utilizing the oligomeric hydrolysate obtained through dilute acid hydrolysis at 120 °C for 60 min using 1% acid through oligomeric-SSF led to 14.2 g/L ABE production, i.e., 65% higher than Process I. In addition, using the oligomeric hydrolysate in SCSF resulted in 24 g/L ABE (16 g/L butanol) production with an overall yield of 182 g ABE/kg cellulose. Process IV showed 191% higher titer and 14% higher yield of ABE production, compared with Process I.