The effect of initial pore volume and lignin content on the enzymatic hydrolysis of softwoods

Mooney, Caitriona; Mansfield, Shawn D.; Touhy, M. G.; Saddler, John N.

doi:10.1016/s0960-8524(97)00181-8

Cited by 393 publications

(238 citation statements)

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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%

“…Previous efforts reported in the literature to assay lignin accessibility to enzymes (lignin being the dominant component in the non-cellulose fraction) can be divided into two classes: (1) extracting lignin from lignocellulosic materials using chemicals (Bernardez et al, 1993;Converse et al, 1990;Gerber et al, 1997;Lee et al, 1994;Mooney et al, 1998;Palonen et al, 2004) and (2) leaving primarily only lignin remaining by hydrolyzing (dissolving away) the hemicellulose and cellulose fractions (Bernardez et al, 1993;Converse et al, 1990;Ooshima et al, 1990;Palonen et al, 2004). Both classes of methods may suffer from the large changes in lignin (or non-cellulose) substrate properties that occur during extraction or hydrolysis.…”

Section: Discussionmentioning

confidence: 99%

“…The total substrate accessibility has been measured previously by using cellulase-size molecule exclusion (Burns et al, 1989;Esteghlalian et al, 2001;Grethlein, 1985;Thompson et al, 1992), low-temperature cellulase adsorption (Gerber et al, 1997;Kumar and Wyman, 2008;Lee et al, 1994;Lu et al, 2002;Mooney et al, 1998) or labeled cellulase (Jeoh et al, 2007;Palonen et al, 2004). However, in pretreated lignocellulose materials it remains relatively challenging to quantitatively differentiate accessibilities for cellulose and non-cellulose fractions.…”

Section: Introductionmentioning

confidence: 99%

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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

201

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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Section: Discussionmentioning

confidence: 76%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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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

201

164

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“…A lignina representa uma barreira para a degradação enzimática da celulose [29][30][31] porque a sua estrutura polimérica tridimensional e amorfa 32 promove a adsorção não específica das enzimas sobre a sua superfície, diminuindo a disponibilidade destas para a sacarificação da celulose ou eventualmente ocasionando a sua inativação. 33 33 No presente trabalho, tanto o percentual de lignina quanto as modificações ocorridas em sua estrutura não foram suficientes para comprometer a acessibilidade das enzimas ao substrato, já que altos índices de sacarificação foram observados em todos os ensaios de hidrólise enzimática.…”

Section: Figura 1 Representação Geométrica Do Efeito De Segunda Ordeunclassified

Efeito do teor de umidade sobre o pré-tratamento a vapor e a hidrólise enzimática do bagaço de cana-de-açúcar

Pitarelo¹,

Silva²,

Peralta-Zamora³

et al. 2012

Quím. Nova

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Recebido em 11/8/11; aceito em 13/4/12; publicado na web em 20/7/2012 EFFECT OF MOISTURE CONTENT IN THE STEAM TREATMENT AND ENZYMATIC HYDROLYSIS OF SUGARCANE BAGASSE. The effect of moisture content in the steam treatment and enzymatic hydrolysis of sugarcane bagasse was evaluated. Steam treatment was perfomed at 195-210 ºC for 4-8 min using cane bagasse with moisture contents in the range 16-100 wt% (dry basis). Increased moisture contents not only had a positive influence in recovery of main cane biomass components but also resulted in better substrates for enzymatic hydrolysis. As a result, drying is not required for optimal pretreatment and enzymatic hydrolysis of sugarcane bagasse, which can be processed into second generation ethanol immediately after crushing and hot water washing.Keywords: sugarcane bagasse; steam explosion; moisture content. INTRODUÇÃOO etanol é um dos principais combustíveis renováveis da atualidade e seu uso em grande escala contribui diretamente para a redução do uso extensivo de combustíveis fósseis no setor automotivo. Sua produção pode ser obtida a partir de diferentes matérias-primas e por diferentes tecnologias de conversão, que podem ser de primeira ou de segunda geração. Enquanto as tecnologias de primeira geração estão baseadas na fermentação alcoólica dos carboidratos presentes, por exemplo, no caldo de cana-de-açúcar (modelo brasileiro) ou em hidrolisados enzimáticos do amido de milho (modelo norte-americano), as tecnologias de segunda geração utilizam resíduos agrícolas e agroindustriais para este mesmo fim. 1-3 Neste caso, o processo fermentativo é baseado nos carboidratos liberados da biomassa vegetal por hidrólise da celulose e das hemiceluloses. 4 A produção de etanol a partir de resíduos agroindustriais representa uma das mais importantes alternativas à consolidação de um modelo sustentável para a produção de combustíveis renováveis. 5,6 Por esta razão, diferentes tecnologias de pré-tratamento, sacarificação (ou hidrólise) e fermentação vêm sendo estudadas em todo mundo para demonstrar a viabilidade comercial deste processo. 3,4,[7][8][9] Neste sentido, a maior parte destes estudos está orientada ao aumento da acessibilidade química da celulose, buscando reduzir a quantidade de enzima necessária para a conversão dos polissacarídeos em açúcares fermentescíveis. 7,10,11 A explosão a vapor tem sido proposta como um dos métodos mais promissores para separar os principais constituintes da biomassa vegetal e aumentar a sua susceptibilidade à bioconversão. 8,[12][13][14][15][16] Este processo, que atua tanto química como fisicamente na estrutura do material lignocelulósico, está baseado no contato direto da biomassa com vapor saturado à alta pressão por um determinado tempo de residência no reator, seguido de descompressão rápida à condição atmosférica (explosão). Ao longo deste processo, as ligações quími-cas que mantêm os componentes macromoleculares da fitobiomassa fortemente associados são em parte quebradas, de forma que, no momento da descompressão, o material é desfibr...

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“…The critical parameters for alkaline pretreatment are reaction temperature, pretreatment time and alkali loading [13]. Apart from that, the accessibility of surface area, the presence of lignin and hemicelluloses would be the key factors affecting the rate of enzymatic hydrolysis of cellulose [14], [15].…”

Section: Introductionmentioning

confidence: 99%

Sodium Hydroxide Pretreatment and Enzymatic Hydrolysis of Oil Palm Mesocarp Fiber

Iberahim¹,

Jahim²,

Harun³

et al. 2013

IJCEA

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Abstract-Sodium hydroxide pretreatment of oil palm mesocarp fiber (OPMF) was carried out with NaOH from 2% to 10% (w/v) at temperature 50 0 C and 70 0 C. The performances of pretreatments were evaluated based on total carbohydrate and reducing sugar including glucose, xylose and arabinose after enzymatic hydrolysis on the pretreated biomass. It was found that the enzymatic hydrolysis had significantly improved when 6% NaOH in 70 0 C applied in the pretreatment process. The highest total reducing sugars produced by means of commercial enzymes was achieved with the overall conversions of glucan and xylan of 87% and 60.73% respectively. The compositions of OPMF in this study are as follows (% g/g dry biomass): glucan, 28.8, xylan, 25.3, arabinan, 1.91, ethanol extractive, 6.32 and ash, 2.60.Index Terms-Enzymatic hydrolysis, glucose, NaOH pretreatment, oil palm mesocarp fiber.

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The effect of initial pore volume and lignin content on the enzymatic hydrolysis of softwoods

Cited by 393 publications

References 12 publications

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

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

Efeito do teor de umidade sobre o pré-tratamento a vapor e a hidrólise enzimática do bagaço de cana-de-açúcar

Sodium Hydroxide Pretreatment and Enzymatic Hydrolysis of Oil Palm Mesocarp Fiber

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