Mechanism of interaction between cellulase action and applied shear force, an hypothesis

Lenting, H.B.M.; Warmoeskerken, Marinus

doi:10.1016/s0168-1656(01)00300-5

Cited by 52 publications

(30 citation statements)

References 34 publications

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“…Palmqvist et al [131] found that mechanical "pre-shearing" of substrate before adding enzymes had no significant effect on enzymatic hydrolysis. Lenting and Warmoeskerken [132] hypothesized that mechanical shear breaks crystalline cellulose regions into amorphous state, making them more amenable to saccharification by enzymes.…”

Section: Effect Of Hydrodynamics Of Mixing On Biomass Hydrolysismentioning

confidence: 99%

Biomass processing into ethanol: pretreatment, enzymatic hydrolysis, fermentation, rheology, and mixing

Volynets

Ein‐Mozaffari

Dahman

2016

Green Processing and Synthesis

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Alternate energy resources need to be developed to amend for depleting fossil fuel reserves. Lignocellulosic biomass is a globally available renewable feedstock that contains a rich sugar platform that can be converted into bioethanol through appropriate processing. The key steps of the process, pretreatment, enzymatic hydrolysis, and fermentation, have undergone considerable amount of research and development over the past decades nearing the process to commercialization. In order for the commercialization to be successful, the process needs to be operated at high dry matter content of biomass, especially in the enzymatic hydrolysis stage that influences ethanol concentration in the final fermentation broth. Biomass becomes a thick paste with challenging rheology for mixing to be effective. As the biomass consistency increases, yield stress increases which limits efficiency of mixing with conventional stirred tanks. The purpose of this review is to provide features and perspectives on processing of biomass into ethanol. Emphasis is placed on rheology and mixing of biomass in the enzymatic hydrolysis step as one of the forefront issues in the field.

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Section: Effect Of Hydrodynamics Of Mixing On Biomass Hydrolysismentioning

confidence: 99%

Biomass processing into ethanol: pretreatment, enzymatic hydrolysis, fermentation, rheology, and mixing

Volynets

Ein‐Mozaffari

Dahman

2016

Green Processing and Synthesis

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“…It should also be remembered that the activity of different cellulases may be modified differently by mechanical agitation, as shown by Cavaco-Paulo et al (1996). Lenting and Warmoeskerken (2001) studied the interaction between cellulase action and shear force on cellulose fibril degradation and hypothesized that (a) a certain threshold of applied shear force is required for optimal cellulase performance, and (b) the lack of the required level of applied shear force cannot be compensated by additional enzyme dosage or extending the incubation time. The same study suggested that forces of variable directions are the most optimal to break the cellulose or to weaken the microfibrils in the fibers.…”

Section: The Reactivity Of Dislocationsmentioning

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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“…Fractions (6.0 ml) were collected at a flow rate of 15 ml h )1 . The active fractions (20)(21)(22)(23)(24)(25)(26)(27)(28), corresponding to the peak of CMCase activity, were combined, dialysed against 0.05 M Tris-HCl buffer and concentrated using a Centrisart filter (Sartorius, Go¨ttingen, Germany), before loading onto a Sephadex G-100 column (2.0·35 cm). Fractions (2 ml; 12-18) corresponding to CMCase activity were collected and the purity was checked on native PAGE.…”

Section: Purification Of Cmcasementioning

confidence: 99%

“…are known to produce a variety of industrially important alkaline hydrolytic extracellular enzymes, such as amylases, cellulases, pectinases and proteases [12,13,16,18,19,31,37]. The potential of cellulases has been revealed in various industrial processes, including food, textiles and laundry, pulp and paper, and agriculture as well as in research and development [2,3,4,5,8,15,21,25,26,27,28,30,34,42,43,44,45].…”

Section: Introductionmentioning

confidence: 99%

Purification and characterisation of alkaline cellulase produced by a novel isolate, Bacillus sphaericus JS1

Singh¹,

Batra²,

Sobti³

2004

Journal of Industrial Microbiology and Biotechnology

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A novel strain of Bacillus sphaericus JS1 producing thermostable alkaline carboxymethyl cellulase (CMCase; endo-1,4-beta-glucanase, E.C. 3.2.1.4) was isolated from soil using Horikoshi medium at pH 9.5. CMCase was purified 192-fold by (NH(4))(2)SO(4) precipitation, ion exchange and gel filtration chromatography, with an overall recovery of 23%. The CMCase is a multimeric protein with a molecular weight estimated by native-PAGE of 183 kDa. Using SDS-PAGE a single band is found at 42 kDa. This suggests presence of four homogeneous polypeptides, which would differentiate this enzyme from other known alkaline cellulases. The activity of the enzyme was significantly inhibited by bivalent cations (Fe(3+) and Hg(2+), 1.0 mM each) and activated by Co(2+), K(+) and Na(+). The purified enzyme revealed the products of carboxymethyl cellulose (CMC) hydrolysis to be CM glucose, cellobiose and cellotriose. Thermostability, pH stability, good hydrolytic capability, and stability in the presence of detergents, surfactants, chelators and commercial proteases make this enzyme potentially useful in laundry detergents.

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Mechanism of interaction between cellulase action and applied shear force, an hypothesis

Cited by 52 publications

References 34 publications

Biomass processing into ethanol: pretreatment, enzymatic hydrolysis, fermentation, rheology, and mixing

Biomass processing into ethanol: pretreatment, enzymatic hydrolysis, fermentation, rheology, and mixing

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

Purification and characterisation of alkaline cellulase produced by a novel isolate, Bacillus sphaericus JS1

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