Surface and pore structure modification of cellulose fibers through cellulase treatment

Park, Sunkyu; Venditti, Richard A.; Abrecht, David G.; Jameel, Hasan; Pawlak, Joel J.; Lee, Jung M.

doi:10.1002/app.25457

Cited by 60 publications

(52 citation statements)

References 25 publications

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“…It has been reported that enzymatic hydrolysis of crystalline cellulose increases the roughness of the cellulose surface, and the structure becomes more receptive for protein adsorption. The surface area of pure cellulosic substance also increases due to enzymatic reaction (Park et al, 2007;Wang et al, 2005). The physical properties of the surface, however, affects only the mass transfer, a minor portion of the overall resistance, and its effect is shown at the initial phase the reaction.…”

Section: Effect Of Physical Properties On Ncc Hydrolysismentioning

confidence: 98%

Mechanism of cellulase reaction on pure cellulosic substrates

Gupta

Lee

2008

Biotech & Bioengineering

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Cellulase reaction mechanism was investigated with the use of following pure cellulosic substrates: Microcrystalline cellulose (Avicel), alpha-cellulose (Sigma), filter paper, cotton, and non-crystalline cellulose (NCC). NCC is amorphous cellulose prepared in our laboratory by treatment with concentrated sulfuric acid. When hydrolyzed with cellulase, NCC produces significant amount of cello-oligosaccharides (COS) as reaction intermediates along with glucose and cellobiose. The COS produced by cellulase were categorized into two different moieties based upon their degree of polymerization (DP): low DP (less than 7) COS (LD-COS) and high DP COS (HD-COS). Endo-glucanase (Endo-G) reacts rapidly on the NCC reducing its DP to 30-60, after which the Endo-G reaction with NCC ceases. HD-COS is produced from NCC by the action of Endo-G, whereas LD-COS is produced by exo-glucanase (Exo-G). beta-Glucosidase (beta-G) hydrolyzes LD-COS to produce cellobiose, but it does not hydrolyze HD-COS. DP of NCC affects the action of Exo-G in such a way that the overall yield is high for high DP NCC. This is in line with previous findings that substrate-recognition by Exo-G requires binding on beta-glucan chain with DP of 10 for the hydrolysis to take place. The individual cellulose chain residues within solid having DP less than 10 therefore remain unreacted. The percentage of the unreacted portion would be lower for high DP NCC, which results high overall conversion. The surface area and the number of reactive sites on the substrate facilitate adsorption of enzyme therefore the initial rate of the hydrolysis. The overall extent of conversion of cellulose, however, is controlled primarily by its inherent characteristics such as DP and crystallinity.

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Section: Effect Of Physical Properties On Ncc Hydrolysismentioning

confidence: 98%

Mechanism of cellulase reaction on pure cellulosic substrates

Gupta

Lee

2008

Biotech & Bioengineering

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“…They speculated that these cavities were the result of initial dislocations, within which cellulases bound to and degraded amorphous and/or crystalline cellulose. Park et al (2007) showed that incubation of fully bleached Kraft pulp fibers with T. reesei cellulase resulted in significant fiber segmentation, i.e. ''cuts'' occur in the cross section, not the axial direction of the fibers.…”

Section: Hydrolysismentioning

confidence: 99%

Cellulose is not just cellulose: a review of dislocations as reactive sites in the enzymatic hydrolysis of cellulose microfibrils

et al. 2012

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Most secondary plant cell walls contain irregular regions known as dislocations or slip planes. Under industrial biorefining conditions dislocations have recently been shown to play a key role during the initial phase of the enzymatic hydrolysis of cellulose in plant cell walls. In this review we chart previous publications that have discussed the structure of dislocations and their susceptibility to hydrolysis. The supramolecular structure of cellulose in dislocations is still unknown. However, it has been shown that cellulose microfibrils continue through dislocations, i.e. dislocations are not regions where free cellulose ends are more abundant than in the bulk cell wall. In more severe cases cracks between fibrils form at dislocations and it is possible that the increased accessibility that these cracks give is the reason why hydrolysis of cellulose starts at these locations. If acid or enzymatic hydrolysis of plant cell walls is carried out simultaneously with the application of shear stress, plant cells such as fibers or tracheids break at their dislocations. At present it is not known whether specific carbohydrate binding modules (CBMs) and/or cellulases preferentially access cellulose at dislocations. From the few studies published so far it seems that no special type of CBM is involved. In one case an endoglucanase was found to preferably bind to dislocations.

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“…The determination of the crystallinity index is highly dependent on the characterisation method [39]. It has been recognized that the actual values of the crystallinity differ according to the measurement principles and analysis techniques used, and that the highest crystallinity index is realized by the X-ray diffraction peak height method, and is bulk measurement performed in the dry state.…”

Section: Crystallinitymentioning

confidence: 99%

“…This was also investigated by scanning electron microscopy (SEM) and results showed a clear decrease in the length of cotton linters and a non-uniformity of particle size after several hours of enzymatic hydrolysis [29,35]. Using Fiber Quality Analyser Park et al [39] showed a clear decrease in particle size and other authors [3,37] correlated the particles size decrease to the increase in surface area.…”

Section: Introductionmentioning

confidence: 99%

Evolution and impact of cellulose architecture during enzymatic hydrolysis by fungal cellulases

Chauve¹,

Barré²,

Tapin-Lingua³

et al. 2013

ABB

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The enzymatic hydrolysis of cellulose is still considered as a main limiting step of the biological production of biofuels from ligno-cellulosic biomass. Glycoside hydrolases from Trichoderma reesei are currently used to produce fermentable glucose units from degradation of cellulose packed in a complex assembly of cellulose microfibrils. The present work describes the structural evolution of two prototypical samples of cellulose (a micro-crystalline cellulose and a bleached sulfite pulp) over 5 length scale orders of magnitude. The results were obtained through wide angle, small angle and ultra-small angles synchrotron X-ray scattering, completed by Small Angle Neutron Scattering and particle size analyzers. These structural evolutions were followed as a function of enzymatic conversion. The results show that whereas there is no change at the nanometer scale, drastic changes occur at micron. The observed decrease of the size of the cellulose particles is accompanied by a smoothing of the crystalline surfaces that can be explained by a two-step mechanism of the enzymatic hydrolysis.

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Surface and pore structure modification of cellulose fibers through cellulase treatment

Cited by 60 publications

References 25 publications

Mechanism of cellulase reaction on pure cellulosic substrates

Mechanism of cellulase reaction on pure cellulosic substrates

Cellulose is not just cellulose: a review of dislocations as reactive sites in the enzymatic hydrolysis of cellulose microfibrils

Evolution and impact of cellulose architecture during enzymatic hydrolysis by fungal cellulases

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