Effect of Sulfuric and Phosphoric Acid Pretreatments on Enzymatic Hydrolysis of Corn Stover

Um, Byung-Hwan; Karim, M. Nazmul; Henk, Linda L.

doi:10.1385/abab:105:1-3:115

Cited by 86 publications

(32 citation statements)

References 11 publications

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“…All samples were neutralized with Ba(OH) 2 , centrifuged at 5,000×g for 10 min, and filtered through 0.22-μm Milipore filters before analysis. The structural carbohydrates laboratory analytical procedure from NREL was modified for use with a Dionex-300 high performance liquid chromatography (HPLC) system [23].…”

Section: Analysis Methodsmentioning

confidence: 99%

“…The United States consumes approximately 25% of the world's oil and natural gas supply [1] and imports 60% of this quantity [2]. National security concerns and a realization that fossil fuels are limited have stimulated the need for investigating technologies to convert lignocellulosic biomass to ethanol for fuel [3].…”

Section: Introductionmentioning

confidence: 99%

“…Hence, the objectives of this study were to: (1) determine the chemical compositions of wheat, barley, and triticale straws (residue after grain harvesting) and triticale, barley, sweet sorghum, and pearl millet hays (harvested when crops are green), (2) investigate suitable acid or alkali pretreatment conditions for different feedstocks, (3) compare efficiency of different enzymes and their concentrations during hydrolysis, (4) determine ethanol yield using selected yeast fermentations.…”

Section: Introductionmentioning

confidence: 99%

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Potential of Agricultural Residues and Hay for Bioethanol Production

Chen

Sharma-Shivappa

Keshwani

et al. 2007

Appl Biochem Biotechnol

157

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Production of bioethanol from agricultural residues and hays (wheat, barley, and triticale straws, and barley, triticale, pearl millet, and sweet sorghum hays) through a series of chemical pretreatment, enzymatic hydrolysis, and fermentation processes was investigated in this study. Composition analysis suggested that the agricultural straws and hays studied contained approximately 28.62-38.58% glucan, 11.19-20.78% xylan, and 22.01-27.57% lignin, making them good candidates for bioethanol production. Chemical pretreatment with sulfuric acid or sodium hydroxide at concentrations of 0.5, 1.0, and 2.0% indicated that concentration and treatment agent play a significant role during pretreatment. After 2.0% sulfuric acid pretreatment at 121°C/15 psi for 60 min, 78.10-81.27% of the xylan in untreated feedstocks was solubilized, while 75.09-84.52% of the lignin was reduced after 2.0% sodium hydroxide pretreatment under similar conditions. Enzymatic hydrolysis of chemically pretreated (2.0% NaOH or H 2 SO 4 ) solids with Celluclast 1.5 LNovozym 188 (cellobiase) enzyme combination resulted in equal or higher glucan and xylan conversion than with Spezyme® CP-xylanase combination. The glucan and xylan conversions during hydrolysis with Celluclast 1.5 L-cellobiase at 40 FPU/g glucan were 78.09 to 100.36% and 74.03 to 84.89%, respectively. Increasing the enzyme loading from 40 to 60 FPU/g glucan did not significantly increase sugar yield. The ethanol yield after fermentation of the hydrolyzate from different feedstocks with Saccharomyces cerevisiae ranged from 0.27 to 0.34 g/g glucose or 52.00-65.82% of the theoretical maximum ethanol yield.

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Section: Analysis Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Potential of Agricultural Residues and Hay for Bioethanol Production

Chen

Sharma-Shivappa

Keshwani

et al. 2007

Appl Biochem Biotechnol

157

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“…Prior to fermentation, however, the carbohydrate polymers cellulose and hemicellulose must be converted to soluble sugars, using a combination of chemical and enzymatic processes (40,42,43). Chemical processes are accompanied by side reactions that produce a mixture of minor products such as alcohols, acids, and aldehydes that have a negative effect on the metabolism of microbial biocatalysts.…”

mentioning

confidence: 99%

Silencing of NADPH-Dependent Oxidoreductase Genes (yqhDanddkgA) in Furfural-Resistant EthanologenicEscherichia coli

Miller

Jarboe

Yomano

et al. 2009

Appl Environ Microbiol

166

232

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Low concentrations of furfural are formed as a side product during the dilute acid hydrolysis of hemicellulose. Growth is inhibited by exposure to furfural but resumes after the complete reduction of furfural to the less toxic furfuryl alcohol. Growth-based selection was used to isolate a furfural-resistant mutant of ethanologenic Escherichia coli LY180, designated strain EMFR9. Based on mRNA expression levels in the parent and mutant in response to furfural challenge, genes encoding 12 oxidoreductases were found to vary by more than twofold (eight were higher in EMFR9; four were higher in the parent). All 12 genes were cloned. When expressed from plasmids, none of the eight genes in the first group increased furfural tolerance in the parent (LY180). Expression of three of the silenced genes (yqhD, dkgA, and yqfA) in EMFR9 was found to decrease furfural tolerance compared to that in the parent. Purified enzymes encoded by yqhD and dkgA were shown to have NADPH-dependent furfural reductase activity. Both exhibited low K m values for NADPH (8 M and 23 M, respectively), similar to those of biosynthetic reactions. Furfural reductase activity was not associated with yqfA. Deleting yqhD and dkgA in the parent (LY180) increased furfural tolerance, but not to the same extent observed in the mutant EMFR9. Together, these results suggest that the process of reducing furfural by using an enzyme with a low K m for NADPH rather than a direct inhibitory action is the primary cause for growth inhibition by low concentrations of furfural.

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“…Um et al (2003) reported the same behavior by pretreating corn stover with both acids under similar conditions.…”

Section: Hemicellulosic Prehydrolysate Productionmentioning

confidence: 58%

Hemicellulose-derived sugars solubilisation of rape straw. Cofermentation of pentoses and hexoses by Escherichia coli

López-Linares

Cara-Corpas

Ruiz

et al. 2015

Span. j. agric. res.

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Bioconversion of hemicellulose sugars is essential for increasing fuel ethanol yields from lignocellulosic biomass. We report for the first time with rape straw, bioethanol production from hemicellulose sugars. Rape straw was pretreated at mild conditions with sulfuric acid to solubilize the hemicellulose fraction. This pretreatment allows obtaining a prehydrolysate, consisting basically in a solution of monomeric hemicellulosic sugars, with low inhibitor concentrations. The remaining water insoluble solid constitutes a cellulose-enriched, free of extractives material. The influence of temperature (120ºC and 130ºC), acid concentration (2-4% w/v) and pretreatment time (30-180 min) on hemicellulose-derived sugars solubilisation was evaluated. The highest hemicellulosic sugars recovery, 72.3%, was achieved at 130ºC with 2% sulfuric acid and 60 min. At these conditions, a concentrated sugars solution, 52.4 g/L, was obtained after three acid consecutive contacts, with 67% xylose and acetic acid concentration above 4.5 g/L. After a detoxification step by activated charcoal or ion-exchange resin, prehydrolysate was fermented by ethanologenic Escherichia coli. An alcoholic solution of 25 g/L and 86% of theoretical ethanol yield was attained after 144 h when the prehydrolysate was detoxified by ion-exchange resin. The results obtained in the present work show sulfuric acid pretreatment under mild conditions and E. coli as an interesting process to exploit hemicellulosic sugars in rape straw.Additional key words: agricultural residue; acid pretreatment; xylose; E. coli; bioethanol production

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Effect of Sulfuric and Phosphoric Acid Pretreatments on Enzymatic Hydrolysis of Corn Stover

Cited by 86 publications

References 11 publications

Potential of Agricultural Residues and Hay for Bioethanol Production

Potential of Agricultural Residues and Hay for Bioethanol Production

Silencing of NADPH-Dependent Oxidoreductase Genes (yqhDanddkgA) in Furfural-Resistant EthanologenicEscherichia coli

Hemicellulose-derived sugars solubilisation of rape straw. Cofermentation of pentoses and hexoses by Escherichia coli

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