Hydrolysis of Nonstarch Carbohydrates of Wheat‐Starch Effluent for Ethanol Production

Palmarola-Adrados, Beatriz; Juhász, Tamás; Galbe, Mats; Zacchi, Guido

doi:10.1021/bp034243h

Cited by 16 publications

(7 citation statements)

References 20 publications

(21 reference statements)

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“…The other 13% of reducing sugars were presumed to be xylose and cellobiose, based on previous research [8, 11]. The culture supernatant of A. cellulolyticus produced large amounts of glucose, while the enzymes from Trichoderma gave a lower glucose ratio.…”

Section: Resultsmentioning

confidence: 99%

“…A. cellulolyticus produces several cellulases and β-glucosidases [8]. Additionally, one of its endo-cellulase components effectively produces glucose from cellobiose [8].…”

Section: Discussionmentioning

confidence: 99%

“…Additionally, one of its endo-cellulase components effectively produces glucose from cellobiose [8]. In this study, CMCase, avicelase, and β-glucosidase were assayed from pH-controlled cultures.…”

Section: Discussionmentioning

confidence: 99%

“…However, before biomass can be used, pretreatment is necessary to break the lignocellulose down into its three major polymeric constituents: cellulose, hemicelluloses, and lignin. Different pretreatment methods such as steam explosion [4, 5], wet oxidation [6, 7], and microwaves [8] have been proposed for lignocellulose fractionation, in which most of the hemicellulose and lignin degradation products are dissolved, and the cellulose is recovered in the solid fraction. The cellulose is either used for paper production or is further hydrolyzed by cellulolytic enzymes or acids to readily usable carbon and energy in the fermentation process.…”

Section: Introductionmentioning

confidence: 99%

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Response of Cellulase Activity in pH-Controlled Cultures of the Filamentous Fungus Acremonium cellulolyticus

Prasetyo

Sumita

Okuda

et al. 2009

Appl Biochem Biotechnol

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Cellulase production was investigated in pH-controlled cultures of Acremonium cellulolyticus. The response to culture pH was investigated for three cellulolytic enzymes, carbomethyl cellulase (CMCase), avicelase, and β-glucosidase. Avicelase and β-glucosidase showed similar profiles, with maximum activity in cultures at pH 5.5–6. The CMCase activity was highest in a pH 4 culture. At an acidic pH, the ratios of CMCase and avicelase activity to cellulase activity defined by filter paper unit were high, but at a neutral pH, the β-glucosidase ratio was high. The pH 6.0 culture showed the highest cellulase activity within the range of pH 3.5–6.5 cultures. The saccharification activity from A. cellulolyticus was compared to those of the cellulolytic enzymes from other species. The A. cellulolyticus culture broth had a saccharification yield comparable to those of the Trichoderma enzymes GC220 and Cellulosin T2, under conditions with the same cellulase activity. The saccharification yields from Solka floc, Avicel, and waste paper, measured as the percent of released reducing sugar to dried substrate, were greater than 80% after 96 h of reaction. The yields were 16% from carboxymethylcellulose and 26% from wood chip refiner. Thus, the A. cellulolyticus enzymes were suitable for converting cellulolytic biomass to reducing sugars for biomass ethanol production. This study is a step toward the establishment of an efficient system to reutilize cellulolytic biomass.

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Section: Resultsmentioning

confidence: 99%

“…A. cellulolyticus produces several cellulases and β-glucosidases [8]. Additionally, one of its endo-cellulase components effectively produces glucose from cellobiose [8].…”

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Response of Cellulase Activity in pH-Controlled Cultures of the Filamentous Fungus Acremonium cellulolyticus

Prasetyo

Sumita

Okuda

et al. 2009

Appl Biochem Biotechnol

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“…Virtually every aspect of life on planet earth (heating, transportation, etc.,) requires energy input in one form or another. Hitherto, this energy need has been met principally by the use of fossil fuel resources [1]. However, it has been recognised that global crude oil reserves are finite, and their depletion is occurring much faster than previously predicted [2,3].…”

Section: Introductionmentioning

confidence: 99%

Intensification of Bioethanol Production by Simultaneous Saccharification and Fermentation (SSF) in an Oscillatory Baffled Reactor (OBR)

Ikwebe¹

2011

Linköping Electronic Conference Proceedings

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Bioethanol is an alternative transport fuel produced mainly by the biochemical conversion of biomasses. This can be carried out efficiently and economically by simultaneous saccharification and fermentation (SSF): a process which integrates the enzymatic saccharification of the cellulose to glucose with the fermentative synthesis of ethanol. However, the SSF unit operation still contributes nearly 50% to the cost of ethanol production. For cellulosic ethanol to be cost competitive, there is the need to intensify the production process in smaller, more efficient and more economical bioreactors. In this work, SSF was performed in an intensified form of plug flow reactor, called the Oscillatory Baffled Reactor (OBR). The OBR is a continuous tubular reactor fitted with equally-spaced orifice plate baffles. An oscillatory component, provided by moving bellows in this design, is superimposed on the net flow through the reactor, generating short-lived vortices due to the interaction of the oscillating fluid with the baffles. This results in uniform mixing in each of the inter-baffle regions, with each behaving as a stirred tank reactor (STR), producing a plug flow residence time distribution (RTD) for the reactor as a whole, in which the mixing effects are largely decoupled from the mean flow (unlike conventional PFRs). The process was evaluated using 2.5% SigmaCell cellulose, 40 FPU cellulase loading/g of cellulose and 10% cellobiase. Saccharomyces cerevisiae was employed as the fermenting organism at 38 o C and pH 4.8. In the first part of this work the use of the OBR resulted in a 7% increase in glucose yield compared to a shake flask, after 48 h of saccharification and 8.0 g/L ethanol in the OBR. This represented 89.8 % of the theoretical yield, as compared to 7.7 g/L in the shake flask representing 81.29%, a difference of 9 percentage point. This increased glucose yield is attributable to better mixing in the OBR.

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Pretreatment of barley husk for bioethanol production

Palmarola-Adrados

Galbe

Zacchi

2004

J of Chemical Tech & Biotech

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This paper reports on the optimization of steam pretreatment of barley husk for high pentose and hexose recovery in the subsequent enzymatic hydrolysis step, as well as high ethanol yield, following simultaneous saccharification and fermentation. The parameters optimized in the steam pretreatment step were residence time (5-15 min), temperature (190-215• C), and concentration of the acid catalyst (0 or 0.5% H 2 SO 4 ). A microwave oven was employed for screening of the optimal conditions to obtain the highest sugar yield following combined pretreatment and enzymatic hydrolysis. The final optimization of the pretreatment prior to enzymatic hydrolysis was performed on a larger scale, in a steam pretreatment unit. Simultaneous saccharification and fermentation was carried out following steam pretreatment on 5 and 10% dry matter steam-pretreated slurries. Fermentability tests were performed to determine the effect of by-products (ie furfural and 5-hydroxymethyl furfural) in the bioconversion of glucose to ethanol by baker's yeast. The maximum glucose yield, 88% of the theoretical, was obtained following steam pretreatment with 0.5% H 2 SO 4 at 200• C for 10 min. Under these conditions, a sugar to ethanol conversion of 81% was attained in simultaneous saccharification and fermentation.

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Hydrolysis of Nonstarch Carbohydrates of Wheat‐Starch Effluent for Ethanol Production

Cited by 16 publications

References 20 publications

Response of Cellulase Activity in pH-Controlled Cultures of the Filamentous Fungus Acremonium cellulolyticus

Response of Cellulase Activity in pH-Controlled Cultures of the Filamentous Fungus Acremonium cellulolyticus

Intensification of Bioethanol Production by Simultaneous Saccharification and Fermentation (SSF) in an Oscillatory Baffled Reactor (OBR)

Pretreatment of barley husk for bioethanol production

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