Effect of hemicellulose and lignin removal on enzymatic hydrolysis of steam pretreated corn stover

Öhgren, Karin; Bura, Renata; Saddler, Jack N.; Zacchi, Guido

doi:10.1016/j.biortech.2006.09.003

Cited by 502 publications

(279 citation statements)

References 20 publications

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“…Both hemicelluloses and lignin form a physical barrier against the enzymatic attack to cellulose. The results corroborate others reported in the literature, making it evident that the removal of these components by the pre-treatment step results in a change in the morphological structure of the lignocellulosic biomass, making it more accessible to the cellulolitic enzymes, and therefore providing an increase in the enzymatic digestibility in the conversion processes of the lignocellulosic biomass into glucose and consequently in ethanol (Öhgren et al, 2006;Liao et al, 2005).…”

Section: Crop Residues To Produce Bioethanolsupporting

confidence: 90%

Assessment of sugarcane trash for agronomic and energy purposes in Brazil

Franco

Pimenta

Carvalho

et al. 2013

Sci. agric. (Piracicaba, Braz.)

107

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Due to new possibilities for using sugarcane (Saccharum spp.) trash for electricity generation, and the production of 2 nd generation ethanol and others chemicals, the interest for its recovery has increased. However, the question of how much trash can be removed from sugarcane field still needs to be clarified. This study evaluated the amount of dry matter, nutrients content, structural compounds and efficiency of the enzymatic hydrolysis of the hydrothermal pretreated materials for tops and dry leaves in samples from sugarcane varieties. Tops and dry leaves present differences in nutrients content and moisture. Therefore, the amount of trash to be collected should not be simply based on percentages, but also should take into account the different fractions of the crop residues. For instance, around 80 % of N, P and K were derived from tops. Therein, the environmental indicators of the entire chain of sugarcane could be benefited because more nutrients would be recycled and less mineral fertilizers might be used for sugarcane production if tops are left on the field. Further, the tops have seven times more moisture than dry leaves and higher amounts of extractives (organic compounds of low molecular weight). Moreover, as the result of yield obtained in the pretreatment steps for dry leaves were superior to the tops and the glucose yields obtained in the enzymatic hydrolysis step were similar, it can be predicted that for second generation ethanol production, it is more viable to recover parts of the dry leaves fraction, leaving the tops on the field.

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Section: Crop Residues To Produce Bioethanolsupporting

confidence: 90%

Assessment of sugarcane trash for agronomic and energy purposes in Brazil

Franco

Pimenta

Carvalho

et al. 2013

Sci. agric. (Piracicaba, Braz.)

107

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“…In particular, the COSLIF-pretreated corn stover has nearly twofold higher hemicellulose composition (6.2%) than has DA-pretreated corn stover (3.4%) but the former has much higher digestibility and faster hydrolysis rates. A common belief is that lignin removal promotes faster and more efficient enzymatic cellulose hydrolysis Chang and Holtzapple, 2000;Esteghlalian et al, 2001;Lee et al, 1994;Mooney et al, 1998;Ohgren et al, 2007;Zhu et al, 2008), but the data presented here suggest that increasing CAC is more important for achieving fast hydrolysis rates and high glucan digestibility because NCAC of the Table II. Total substrate accessibility to cellulase (TSAC), cellulose accessibility to cellulase (CAC), and non-cellulose accessibility to cellulase (NCAC) values of corn stover samples before pretreatment and after COSLIF and DA pretreatment.…”

Section: Discussionmentioning

confidence: 76%

Comparative study of corn stover pretreated by dilute acid and cellulose solvent‐based lignocellulose fractionation: Enzymatic hydrolysis, supramolecular structure, and substrate accessibility

Zhu

Sathitsuksanoh

Vinzant

et al. 2009

Biotech & Bioengineering

200

164

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Liberation of fermentable sugars from recalcitrant biomass is among the most costly steps for emerging cellulosic ethanol production. Here we compared two pretreatment methods (dilute acid, DA, and cellulose solvent and organic solvent lignocellulose fractionation, COSLIF) for corn stover. At a high cellulase loading [15 filter paper units (FPUs) or 12.3 mg cellulase per gram of glucan], glucan digestibilities of the corn stover pretreated by DA and COSLIF were 84% at hour 72 and 97% at hour 24, respectively. At a low cellulase loading (5 FPUs per gram of glucan), digestibility remained as high as 93% at hour 24 for the COSLIF-pretreated corn stover but reached only $60% for the DA-pretreated biomass. Quantitative determinations of total substrate accessibility to cellulase (TSAC), cellulose accessibility to cellulase (CAC), and non-cellulose accessibility to cellulase (NCAC) based on adsorption of a nonhydrolytic recombinant protein TGC were measured for the first time. The COSLIF-pretreated corn stover had a CAC of 11.57 m 2 /g, nearly twice that of the DA-pretreated biomass (5.89 m 2 /g). These results, along with scanning electron microscopy images showing dramatic structural differences between the DA-and COSLIF-pretreated samples, suggest that COSLIF treatment disrupts microfibrillar structures within biomass while DA treatment mainly removes hemicellulose. Under the tested conditions COSLIF treatment breaks down lignocellulose structure more extensively than DA treatment, producing a more enzymatically reactive material with a higher CAC accompanied by faster hydrolysis rates and higher enzymatic digestibility.

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“…As mentioned above, Celluclast 1.5 L contains xylan-degrading enzymes, but it has been reported that these were not enough to remove hemicellulose even when chemical pretreatment of biomass such as steam with an acid catalyst 11) and ammonia fiber expansion 27) was used. Hence, we added a hemicellulase, Multifect xylanase, to the reaction solution, and increased yields of pentoses and glucose were observed ( Figs.…”

Section: Effect Of Hemicellulose On Enzymatic Hydrolysis Of the Plantmentioning

confidence: 99%

“…7,8) Hemicellulose is known to coat the cellulose microfibrils in the plant cell wall, 9) forming a physical barrier to access by hydrolytic enzymes, and removal of hemicellulose has been reported to increase the enzymatic hydrolysis of cellulose. 10,11) Miscanthus sinensis, a perennial grass performing C4-type photosynthesis distributed widely in Japan, 12) was traditionally used as a roofing material for houses, but this is very rare now and the plant is considered a weed. M. sinensis grows rapidly, with an annual yield of 20-26 tons dry weight per hectare, 13) and it grows well even in acid sulphate soils.…”

mentioning

confidence: 99%