A comparative study of ethanol production using dilute acid, ionic liquid and AFEX™ pretreated corn stover

Nirmal Uppugundla, Leonardo Da Costa Sousa, Shishir P S Chundawat, Xiurong Yu, Blake Simmons, Seema Singh, Xiadi Gao, Rajeev Kumar, Charles E. Wyman, Bruce E. Dale, Venkatesh Balan

    Research output: Research - peer-reviewArticle

    • 74 Citations

    Abstract

    Background: In a biorefinery producing cellulosic biofuels, biomass pretreatment will significantly influence the efficacy of enzymatic hydrolysis and microbial fermentation. Comparison of different biomass pretreatment techniques by studying the impact of pretreatment on downstream operations at industrially relevant conditions and performing comprehensive mass balances will help focus attention on necessary process improvements, and thereby help reduce the cost of biofuel production. Results: An on-going collaboration between the three US Department of Energy (DOE) funded bioenergy research centers (Great Lakes Bioenergy Research Center (GLBRC), Joint BioEnergy Institute (JBEI) and BioEnergy Science Center (BESC)) has given us a unique opportunity to compare the performance of three pretreatment processes, notably dilute acid (DA), ionic liquid (IL) and ammonia fiber expansion (AFEXTM), using the same source of corn stover. Separate hydrolysis and fermentation (SHF) was carried out using various combinations of commercially available enzymes and engineered yeast (Saccharomyces cerevisiae 424A) strain. The optimal commercial enzyme combination (Ctec2: Htec2: Multifect Pectinase, percentage total protein loading basis) was evaluated for each pretreatment with a microplate-based assay using milled pretreated solids at 0.2% glucan loading and 15 mg total protein loading/g of glucan. The best enzyme combinations were 67:33:0 for DA, 39:33:28 for IL and 67:17:17 for AFEX. The amounts of sugar (kg) (glucose: xylose: total gluco- and xylo-oligomers) per 100 kg of untreated corn stover produced after 72 hours of 6% glucan loading enzymatic hydrolysis were: DA (25:2:2), IL (31:15:2) and AFEX (26:13:7). Additionally, the amounts of ethanol (kg) produced per 100 kg of untreated corn stover and the respective ethanol metabolic yield (%) achieved with exogenous nutrient supplemented fermentations were: DA (14.0, 92.0%), IL (21.2, 93.0%) and AFEX (20.5, 95.0%), respectively. The reason for lower ethanol yield for DA is because most of the xylose produced during the pretreatment was removed and not converted to ethanol during fermentation. Conclusions: Compositional analysis of the pretreated biomass solids showed no significant change in composition for AFEX treated corn stover, while about 85% of hemicellulose was solubilized after DA pretreatment, and about 90% of lignin was removed after IL pretreatment. As expected, the optimal commercial enzyme combination was different for the solids prepared by different pretreatment technologies. Due to loss of nutrients during the pretreatment and washing steps, DA and IL pretreated hydrolysates required exogenous nutrient supplementation to ferment glucose and xylose efficiently, while AFEX pretreated hydrolysate did not require nutrient supplementation.

    LanguageEnglish (US)
    Article number72
    JournalBiotechnology for Biofuels
    Volume7
    Issue number1
    DOIs
    StatePublished - May 13 2014

    Profile

    ethanol
    comparative study
    maize
    acid
    ionic liquid
    Ionic Liquids
    Zea mays
    Ethanol
    Acids
    Ionic liquids
    bioenergy
    fermentation
    enzyme
    nutrient
    Fermentation
    Food
    Enzymes
    Nutrients
    hydrolysis
    biomass

    Keywords

    • AFEX
    • Cellulosic ethanol
    • Dilute acid
    • Enzymatic hydrolysis
    • Ionic liquid
    • Pretreatment

    ASJC Scopus subject areas

    • Energy(all)
    • Management, Monitoring, Policy and Law
    • Biotechnology
    • Renewable Energy, Sustainability and the Environment
    • Applied Microbiology and Biotechnology

    Cite this

    Uppugundla, N., Da Costa Sousa, L., Chundawat, S. P. S., Yu, X., Simmons, B., Singh, S., ... Balan, V. (2014). A comparative study of ethanol production using dilute acid, ionic liquid and AFEX™ pretreated corn stover. Biotechnology for Biofuels, 7(1), [72]. DOI: 10.1186/1754-6834-7-72

    A comparative study of ethanol production using dilute acid, ionic liquid and AFEX™ pretreated corn stover. / Uppugundla, Nirmal; Da Costa Sousa, Leonardo; Chundawat, Shishir P S; Yu, Xiurong; Simmons, Blake; Singh, Seema; Gao, Xiadi; Kumar, Rajeev; Wyman, Charles E.; Dale, Bruce E.; Balan, Venkatesh.

    In: Biotechnology for Biofuels, Vol. 7, No. 1, 72, 13.05.2014.

    Research output: Research - peer-reviewArticle

    Uppugundla, N, Da Costa Sousa, L, Chundawat, SPS, Yu, X, Simmons, B, Singh, S, Gao, X, Kumar, R, Wyman, CE, Dale, BE & Balan, V 2014, 'A comparative study of ethanol production using dilute acid, ionic liquid and AFEX™ pretreated corn stover' Biotechnology for Biofuels, vol 7, no. 1, 72. DOI: 10.1186/1754-6834-7-72
    Uppugundla N, Da Costa Sousa L, Chundawat SPS, Yu X, Simmons B, Singh S et al. A comparative study of ethanol production using dilute acid, ionic liquid and AFEX™ pretreated corn stover. Biotechnology for Biofuels. 2014 May 13;7(1). 72. Available from, DOI: 10.1186/1754-6834-7-72
    Uppugundla, Nirmal ; Da Costa Sousa, Leonardo ; Chundawat, Shishir P S ; Yu, Xiurong ; Simmons, Blake ; Singh, Seema ; Gao, Xiadi ; Kumar, Rajeev ; Wyman, Charles E. ; Dale, Bruce E. ; Balan, Venkatesh. / A comparative study of ethanol production using dilute acid, ionic liquid and AFEX™ pretreated corn stover. In: Biotechnology for Biofuels. 2014 ; Vol. 7, No. 1.
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    abstract = "Background: In a biorefinery producing cellulosic biofuels, biomass pretreatment will significantly influence the efficacy of enzymatic hydrolysis and microbial fermentation. Comparison of different biomass pretreatment techniques by studying the impact of pretreatment on downstream operations at industrially relevant conditions and performing comprehensive mass balances will help focus attention on necessary process improvements, and thereby help reduce the cost of biofuel production. Results: An on-going collaboration between the three US Department of Energy (DOE) funded bioenergy research centers (Great Lakes Bioenergy Research Center (GLBRC), Joint BioEnergy Institute (JBEI) and BioEnergy Science Center (BESC)) has given us a unique opportunity to compare the performance of three pretreatment processes, notably dilute acid (DA), ionic liquid (IL) and ammonia fiber expansion (AFEXTM), using the same source of corn stover. Separate hydrolysis and fermentation (SHF) was carried out using various combinations of commercially available enzymes and engineered yeast (Saccharomyces cerevisiae 424A) strain. The optimal commercial enzyme combination (Ctec2: Htec2: Multifect Pectinase, percentage total protein loading basis) was evaluated for each pretreatment with a microplate-based assay using milled pretreated solids at 0.2% glucan loading and 15 mg total protein loading/g of glucan. The best enzyme combinations were 67:33:0 for DA, 39:33:28 for IL and 67:17:17 for AFEX. The amounts of sugar (kg) (glucose: xylose: total gluco- and xylo-oligomers) per 100 kg of untreated corn stover produced after 72 hours of 6% glucan loading enzymatic hydrolysis were: DA (25:2:2), IL (31:15:2) and AFEX (26:13:7). Additionally, the amounts of ethanol (kg) produced per 100 kg of untreated corn stover and the respective ethanol metabolic yield (%) achieved with exogenous nutrient supplemented fermentations were: DA (14.0, 92.0%), IL (21.2, 93.0%) and AFEX (20.5, 95.0%), respectively. The reason for lower ethanol yield for DA is because most of the xylose produced during the pretreatment was removed and not converted to ethanol during fermentation. Conclusions: Compositional analysis of the pretreated biomass solids showed no significant change in composition for AFEX treated corn stover, while about 85% of hemicellulose was solubilized after DA pretreatment, and about 90% of lignin was removed after IL pretreatment. As expected, the optimal commercial enzyme combination was different for the solids prepared by different pretreatment technologies. Due to loss of nutrients during the pretreatment and washing steps, DA and IL pretreated hydrolysates required exogenous nutrient supplementation to ferment glucose and xylose efficiently, while AFEX pretreated hydrolysate did not require nutrient supplementation.",
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    author = "Nirmal Uppugundla and {Da Costa Sousa}, Leonardo and Chundawat, {Shishir P S} and Xiurong Yu and Blake Simmons and Seema Singh and Xiadi Gao and Rajeev Kumar and Wyman, {Charles E.} and Dale, {Bruce E.} and Venkatesh Balan",
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    T1 - A comparative study of ethanol production using dilute acid, ionic liquid and AFEX™ pretreated corn stover

    AU - Uppugundla,Nirmal

    AU - Da Costa Sousa,Leonardo

    AU - Chundawat,Shishir P S

    AU - Yu,Xiurong

    AU - Simmons,Blake

    AU - Singh,Seema

    AU - Gao,Xiadi

    AU - Kumar,Rajeev

    AU - Wyman,Charles E.

    AU - Dale,Bruce E.

    AU - Balan,Venkatesh

    PY - 2014/5/13

    Y1 - 2014/5/13

    N2 - Background: In a biorefinery producing cellulosic biofuels, biomass pretreatment will significantly influence the efficacy of enzymatic hydrolysis and microbial fermentation. Comparison of different biomass pretreatment techniques by studying the impact of pretreatment on downstream operations at industrially relevant conditions and performing comprehensive mass balances will help focus attention on necessary process improvements, and thereby help reduce the cost of biofuel production. Results: An on-going collaboration between the three US Department of Energy (DOE) funded bioenergy research centers (Great Lakes Bioenergy Research Center (GLBRC), Joint BioEnergy Institute (JBEI) and BioEnergy Science Center (BESC)) has given us a unique opportunity to compare the performance of three pretreatment processes, notably dilute acid (DA), ionic liquid (IL) and ammonia fiber expansion (AFEXTM), using the same source of corn stover. Separate hydrolysis and fermentation (SHF) was carried out using various combinations of commercially available enzymes and engineered yeast (Saccharomyces cerevisiae 424A) strain. The optimal commercial enzyme combination (Ctec2: Htec2: Multifect Pectinase, percentage total protein loading basis) was evaluated for each pretreatment with a microplate-based assay using milled pretreated solids at 0.2% glucan loading and 15 mg total protein loading/g of glucan. The best enzyme combinations were 67:33:0 for DA, 39:33:28 for IL and 67:17:17 for AFEX. The amounts of sugar (kg) (glucose: xylose: total gluco- and xylo-oligomers) per 100 kg of untreated corn stover produced after 72 hours of 6% glucan loading enzymatic hydrolysis were: DA (25:2:2), IL (31:15:2) and AFEX (26:13:7). Additionally, the amounts of ethanol (kg) produced per 100 kg of untreated corn stover and the respective ethanol metabolic yield (%) achieved with exogenous nutrient supplemented fermentations were: DA (14.0, 92.0%), IL (21.2, 93.0%) and AFEX (20.5, 95.0%), respectively. The reason for lower ethanol yield for DA is because most of the xylose produced during the pretreatment was removed and not converted to ethanol during fermentation. Conclusions: Compositional analysis of the pretreated biomass solids showed no significant change in composition for AFEX treated corn stover, while about 85% of hemicellulose was solubilized after DA pretreatment, and about 90% of lignin was removed after IL pretreatment. As expected, the optimal commercial enzyme combination was different for the solids prepared by different pretreatment technologies. Due to loss of nutrients during the pretreatment and washing steps, DA and IL pretreated hydrolysates required exogenous nutrient supplementation to ferment glucose and xylose efficiently, while AFEX pretreated hydrolysate did not require nutrient supplementation.

    AB - Background: In a biorefinery producing cellulosic biofuels, biomass pretreatment will significantly influence the efficacy of enzymatic hydrolysis and microbial fermentation. Comparison of different biomass pretreatment techniques by studying the impact of pretreatment on downstream operations at industrially relevant conditions and performing comprehensive mass balances will help focus attention on necessary process improvements, and thereby help reduce the cost of biofuel production. Results: An on-going collaboration between the three US Department of Energy (DOE) funded bioenergy research centers (Great Lakes Bioenergy Research Center (GLBRC), Joint BioEnergy Institute (JBEI) and BioEnergy Science Center (BESC)) has given us a unique opportunity to compare the performance of three pretreatment processes, notably dilute acid (DA), ionic liquid (IL) and ammonia fiber expansion (AFEXTM), using the same source of corn stover. Separate hydrolysis and fermentation (SHF) was carried out using various combinations of commercially available enzymes and engineered yeast (Saccharomyces cerevisiae 424A) strain. The optimal commercial enzyme combination (Ctec2: Htec2: Multifect Pectinase, percentage total protein loading basis) was evaluated for each pretreatment with a microplate-based assay using milled pretreated solids at 0.2% glucan loading and 15 mg total protein loading/g of glucan. The best enzyme combinations were 67:33:0 for DA, 39:33:28 for IL and 67:17:17 for AFEX. The amounts of sugar (kg) (glucose: xylose: total gluco- and xylo-oligomers) per 100 kg of untreated corn stover produced after 72 hours of 6% glucan loading enzymatic hydrolysis were: DA (25:2:2), IL (31:15:2) and AFEX (26:13:7). Additionally, the amounts of ethanol (kg) produced per 100 kg of untreated corn stover and the respective ethanol metabolic yield (%) achieved with exogenous nutrient supplemented fermentations were: DA (14.0, 92.0%), IL (21.2, 93.0%) and AFEX (20.5, 95.0%), respectively. The reason for lower ethanol yield for DA is because most of the xylose produced during the pretreatment was removed and not converted to ethanol during fermentation. Conclusions: Compositional analysis of the pretreated biomass solids showed no significant change in composition for AFEX treated corn stover, while about 85% of hemicellulose was solubilized after DA pretreatment, and about 90% of lignin was removed after IL pretreatment. As expected, the optimal commercial enzyme combination was different for the solids prepared by different pretreatment technologies. Due to loss of nutrients during the pretreatment and washing steps, DA and IL pretreated hydrolysates required exogenous nutrient supplementation to ferment glucose and xylose efficiently, while AFEX pretreated hydrolysate did not require nutrient supplementation.

    KW - AFEX

    KW - Cellulosic ethanol

    KW - Dilute acid

    KW - Enzymatic hydrolysis

    KW - Ionic liquid

    KW - Pretreatment

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