Acid hydrolysis of bacterial cellulose reveals different modes of synergistic action between cellobiohydrolase I and endoglucanase I

Väljamaë, Priit; Sild, Veljo; Nutt, Anu; Pettersson, Göran; Johansson, Gunnar

doi:10.1046/j.1432-1327.1999.00853.x

Cited by 134 publications

(140 citation statements)

References 34 publications

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“…Cotton (Hoshino et al, 1997;Sinitsyn et al, 1991), bacterial cellulose from Aacetobacter xylinum (Boisset et al, 1999;Gilkes et al, 1992;Valjamae et al, 1999), and cellulose from the alga Valonia ventricosa (Boisset et al, 1999;Fierobe et al, 2002) provide examples of highly crystalline cellulose, while phosphoric acid swollen cellulose and ball-milled cellulose are regarded as amorphous cellulose (Hoshino et al, 1997; (Mosier et al, 1999). c: Organization of lignocellulose origanization into elementary fibrils and microfibrils (Klein andSnodgrass, 1993).…”

Section: Crystallinity Index (Cri)mentioning

confidence: 99%

“…Similarly, the DP of natural cotton can be as high as 15,000, but is reduced to 1,000 -3,000 or less in the preparation of cotton linters involving treatment to accomplish dewaxing and whitening (Kleman-Leyer et al, 1992Okazaki and MooYoung, 1978;Ryu and Lee, 1982), and filter paper made from cotton pulp has a DP of 500 -1,000 or higher (Nisizawa, 1973;Kongruang et al, 2004). Bacterial cellulose (BC) has an average DP of 2,000 -3,000 (Hestrin, 1963;Fierobe et al, 2002;Valjamae et al, 1999), while bacterial microcrystalline cellulose (BMCC) prepared by treatment of BC with acids ranges from 130 -1,300, depending on hydrolysis conditions (Valjamae et al, 1999). The DP of phosphoric-acid swollen cellulose (PASC) ranges from 30 to more than 1,000 Krassig, 1985;Petre et al, 1981;Wood and McCrae, 1972), depending on the DP of the starting substrate (Wood, 1988;Hoshino et al, 1997), as well as the phosphoric acid incubation time and temperature (Krassig, 1993).…”

Section: Degree Of Polymerizationmentioning

confidence: 99%

“…Bacterial cellulose (BC) is prepared from the pellicle produced by Acetobacter xylinum (ATCC 23769) (Hestrin, 1963) or from Nata de Coco (Daiwa Fine Produces, Singapore; Boisset et al, 2000). Bacterial microcrystalline cellulose (BMCC) is prepared from BC by partial acid hydrolysis to remove amorphous cellulose (Valjamae et al, 1999). Cotton cellulose is made from natural cotton after removing impurities such as wax, pectin, and colored matter (Corbett, 1963).…”

Section: Preparation and Properties Of Model Substratesmentioning

confidence: 99%

“…It is widely observed that the heterogeneous structure of cellulose gives rise to a rapid decrease in rate as hydrolysis proceeds, even when the effects of cellulase deactivation and product inhibition are taken into account (Zhang et al, 1999;Valjamae et al, 1999). Explaining this observation at a mechanistic level is an outstanding issue, with important fundamental and applied implications.…”

Section: Cellulose Hydrolysis On the Mechanism Of Cellulose Hydrolysimentioning

confidence: 99%

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Toward an aggregated understanding of enzymatic hydrolysis of cellulose: Noncomplexed cellulase systems

Zhang

Lynd

2004

Biotech & Bioengineering

1,659

1,284

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Information pertaining to enzymatic hydrolysis of cellulose by noncomplexed cellulase enzyme systems is reviewed with a particular emphasis on development of aggregated understanding incorporating substrate features in addition to concentration and multiple cellulase components. Topics considered include properties of cellulose, adsorption, cellulose hydrolysis, and quantitative models. A classification scheme is proposed for quantitative models for enzymatic hydrolysis of cellulose based on the number of solubilizing activities and substrate state variables included. We suggest that it is timely to revisit and reinvigorate functional modeling of cellulose hydrolysis, and that this would be highly beneficial if not necessary in order to bring to bear the large volume of information available on cellulase components on the primary applications that motivate interest in the subject. B

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Section: Crystallinity Index (Cri)mentioning

confidence: 99%

Section: Degree Of Polymerizationmentioning

confidence: 99%

Section: Preparation and Properties Of Model Substratesmentioning

confidence: 99%

Section: Cellulose Hydrolysis On the Mechanism Of Cellulose Hydrolysimentioning

confidence: 99%

See 2 more Smart Citations

Toward an aggregated understanding of enzymatic hydrolysis of cellulose: Noncomplexed cellulase systems

Zhang

Lynd

2004

Biotech & Bioengineering

1,659

1,284

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“…The endo-exo synergism is a highly effective synergism that has been reported in many studies and plays critical role in the hydrolysis rates and yields (Andersen 2007;Medve et al 1998;Väljamäe et al 1999;Zhang and Lynd 2004). The model was simulated for hydrolysis of filter paper and cotton for individual and combined EG and CBH I. Simulations were performed for 48 h assuming 25 g/L substrate concentration at enzyme loadings of 10 mg/g glucans (individually and total of 20 mg/g glucans in mixture, with EG to CBH I ratio of 1:1).…”

Section: Endo-exo Synergismmentioning

confidence: 99%

Development and validation of a stochastic molecular model of cellulose hydrolysis by action of multiple cellulase enzymes

Kumar

Murthy

2017

Bioresour. Bioprocess.

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Background:Cellulose is hydrolyzed to sugar monomers by the synergistic action of multiple cellulase enzymes: endo-β-1,4-glucanase, exo-β-1,4 cellobiohydrolase, and β-glucosidase. Realistic modeling of this process for various substrates, enzyme combinations, and operating conditions poses severe challenges. A mechanistic hydrolysis model was developed using stochastic molecular modeling approach. Cellulose structure was modeled as a cluster of microfibrils, where each microfibril consisted of several elementary fibrils, and each elementary fibril was represented as three-dimensional matrices of glucose molecules. Using this in-silico model of cellulose substrate, multiple enzyme actions represented by discrete hydrolysis events were modeled using Monte Carlo simulation technique. In this work, the previous model was modified, mainly to incorporate simultaneous action enzymes from multiple classes at any instant of time to account for the enzyme crowding effect, a critical phenomenon during hydrolysis process. Some other modifications were made to capture more realistic expected interactions during hydrolysis. The results were validated with experimental data of pure cellulose (Avicel, filter paper, and cotton) hydrolysis using purified enzymes from Trichoderma reesei for various hydrolysis conditions. Results:Hydrolysis results predicted by model simulations showed a good fit with the experimental data under all hydrolysis conditions. Current model resulted in more accurate predictions of sugar concentrations compared to previous version of the model. Model results also successfully simulated experimentally observed trends, such as product inhibition, low cellobiohydrolase activity on high DP substrates, low endoglucanases activity on a crystalline substrate, and inverse relationship between the degree of synergism and substrate degree of polymerization emerged naturally from the model. Conclusions

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Optimized mixtures of recombinant Humicola insolens cellulases for the biodegradation of crystalline cellulose

Boisset

Petrequin

Chanzy

et al. 2000

Biotech & Bioengineering

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The digestion of bacterial cellulose ribbons by ternary mixtures of enzymes consisting of recombinant cellulases (two cellobiohydrolases, Cel6A and Cel7A, and the endoglucanase Cel45A) from Humicola insolens was investigated over a wide range of mixture composition. The extent of digestion was followed by soluble sugar release (saccharification) analysis together with transmission electron microscopy (TEM) observations. It was found that the addition of minute quantities of Cel45A induced a spectacular increase in saccharification of the substrate with either Cel7A or the mixture of Cel6A and Cel7A. Conversely, only a moderate saccharification resulted from the mixing of Cel45A and Cel6A. This difference is believed to originate from (1) the occasional endo character of Cel6A and (2) the competition of Cel6A and Cel45A for the substrate sites that are sensitive to endo activity. Interestingly, the mixture of enzymes giving rise to the highest saccharification rate did not always correspond to mixtures of enzymes generating the highest synergy. TEM images revealed that the bacterial cellulose ribbons became at the same time cut and narrowed down under the action of an optimized mixture of the three enzymes. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 72: 339–345, 2001.

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Acid hydrolysis of bacterial cellulose reveals different modes of synergistic action between cellobiohydrolase I and endoglucanase I

Cited by 134 publications

References 34 publications

Toward an aggregated understanding of enzymatic hydrolysis of cellulose: Noncomplexed cellulase systems

Toward an aggregated understanding of enzymatic hydrolysis of cellulose: Noncomplexed cellulase systems

Development and validation of a stochastic molecular model of cellulose hydrolysis by action of multiple cellulase enzymes

Optimized mixtures of recombinant Humicola insolens cellulases for the biodegradation of crystalline cellulose

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