Adsorption of Trichoderma reesei CBH I and EG II and their catalytic domains on steam pretreated softwood and isolated lignin

Palonen, Hetti; Tjerneld, Folke; Zacchi, Guido; Tenkanen, Maija

doi:10.1016/j.jbiotec.2003.09.011

Cited by 448 publications

(337 citation statements)

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“…The more open nature of the active site may reveal the aromatic residues to lignin, which may lead to adsorption through hydrophobic interactions. 12 This high affinity of EG I with lignin causes a more extensive inhibition for cellulose hydrolysis.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Preferential Adsorption and Activity of Monocomponent Cellulases on Lignocellulose Thin Films with Varying Lignin Content

et al. 2013

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Understanding the enzymatic hydrolysis of cellulose and the influence of lignin in the process are critical for viable production of fuels and chemicals from lignocellulosic biomass. The interactions of monocomponent cellulases with cellulose and lignin substrates were investigated by using thin films supported on quartz crystal microgravimetry (QCM) resonators. Trichoderma reesei exoglucanase (CBH-I) and endoglucanase (EG-I) bound strongly to both cellulose and lignin but EG-I exhibited a distinctive higher affinity with lignin, causing a more extensive inhibition of the cellulolytic reactions. CBH-I was found to penetrate into the bulk of the cellulose substrate increasing the extent of hydrolysis and film deconstruction. In the absence of a cellulose binding domain (CBD) and a linker, the CBH-I core adsorbed slowly and was not able to penetrate into the film. Conversely to CBH-I, EG-I exhibited activity only on the surface of the lignocellulose substrate even when containing a CBD and a linker. Interestingly, EG-I displayed a clearly different interaction profile as a function of contact time registered by QCM.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Preferential Adsorption and Activity of Monocomponent Cellulases on Lignocellulose Thin Films with Varying Lignin Content

et al. 2013

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“…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%

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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“…A maioria dos reagentes, enzimas, água e demais substâncias reativas penetra inicialmente nas regiões amorfas e na superfície das regiões cristalinas, deixando as regiões intracristalinas intactas. A adsorção de enzimas sobre o substrato, durante a hidrólise, é um fenômeno desejado, uma vez que a conversão é extremamente dependente da ligação produtiva da enzima ao substrato, principalmente quando estas possuem o domínio de ligação a carboidratos (CBD) (PALONEN et al, 2004). A ligação das enzimas hidrolíticas ao substrato envolve a fixação de aminoácidos aromáticos, principalmente os resíduos de tirosina, na face dos anéis dos açúcares.…”

Section: Extrativosunclassified

“…Este efeito é chamado "ligação improdutiva" e tem sido observado para várias biomassas (CHERNOGLAZOV et al, 1988;PALONEN et al, 2004;BERLIN et al, 2005a;NAKAGAME et al, 2010;RAHIKAINEN et al, 2011).…”

Section: Extrativosunclassified

Sacarificação enzimática de bagaços de cana-de-açúcar pré-tratados com sulfito ácido

Marassi¹

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A Deus, por me dar a vida e me manter sempre firme nos meus propósitos. À Professora Dra. Adriane Maria Ferreira Milagres, pela orientação, amizade, confiança e disponibilidade.À minha mãe, Maria José, in memoriam, por todos os ensinamentos e anos dedicados a moldar meu caráter e me encher de amor e carinho.Ao meu pai, Marcelo Monte, pelo exemplo de sabedoria, força e persistência.Às minhas filhas, gêmeas, presentes de Deus, Mariana e Cecília, que chegaram para me dar força e ânimo para vencer mais essa etapa e com seus 'chutinhos' me incentivaram a terminar a escrita da tese.Aos meus irmãos Marcelo, Regina, Isabel e Elisa que mesmo à distância sempre me incentivaram, apoiaram e confiaram em mim.Ao meu marido, Renato, pela paciência, amor e apoio constante. The enzymatic hydrolysis of sugarcane bagasse, to obtain a high efficiency of conversion of polysaccharides in monosaccharides, is dependent on factors related to the morphology and chemical composition. Therefore, a pretreatment step is necessary in order to obtain a less recalcitrant substrate. The main objective of this work was to study acid sulfite pretreatment in different samples of sugarcane bagasse, to verify how the changes in the fibers could influence the enzymatic conversion of cellulose. The methodology of acid sulfite pretreatment is based on the chemical modification of the substrate by removing hemicellulose and lignin sulfonation, followed by mechanical refining. The effect of the addition of Na 2 SO 3 at concentrations of 0 to 10 % (w/w) with constant loading of 2.5 % (w/w) H 2 SO 4 was evaluated to pretreat commercial variety of bagasse (VC) at 121 °C. The effect on the variation of pretreatment temperature (130 °C, 150 °C and 160 °C) was evaluated to the acid sulfite reaction with the VC and hybrids H89, H146, H166. The changes in the chemical composition of bagasses were determined, as well as the sulfonic acid groups content, the degree of water retention value and the X-rays diffraction pattern. Methods such as scanning electron microscopy, FTIR and thermal analysis (TGA and DSC) completed the characterization of the pretreated bagasse. The effect of enzyme loading was evaluated in the hydrolysis of pretreated bagasse, fixing the consistency at 2 % (w/v) and cellulases derived from Trichoderma reesei mixed by β-glucosidase of Aspergillus niger in enzyme loadings of 5:10, 10:20 and 20:40 FPU:IU, respectively. It was observed that increasing the sulfite loadings, as well the temperature of pretreatment resulted in high removal of hemicellulose and lignin. The removal of hemicellulose reached 70 % in the pretreated bagasses at 160 °C. The water retention values were lower in bagasses with low hemicellulose content and the crystallinity index (ICcorr) calculated and corrected by pretreatment yields increased under high temperature. The severity factor pretreatment did not correlate with the enzymatic conversion of cellulose and hemicellulose, but the highest removal of hemicellulose promoted a better action of enzymes on substrates. The ef...

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Adsorption of Trichoderma reesei CBH I and EG II and their catalytic domains on steam pretreated softwood and isolated lignin

Cited by 448 publications

References 32 publications

Preferential Adsorption and Activity of Monocomponent Cellulases on Lignocellulose Thin Films with Varying Lignin Content

Preferential Adsorption and Activity of Monocomponent Cellulases on Lignocellulose Thin Films with Varying Lignin Content

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

Sacarificação enzimática de bagaços de cana-de-açúcar pré-tratados com sulfito ácido

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