Substrate reactivity as a function of the extent of reaction in the enzymatic hydrolysis of lignocellulose

Desai, Sunil G.; Converse, Alvin O.

doi:10.1002/(sici)1097-0290(19971220)56:6<650::aid-bit8>3.0.co;2-m

Cited by 79 publications

(45 citation statements)

References 17 publications

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“…Several groups have undertaken "restart" experiments wherein a partial hydrolysis is conducted, cellulase is removed, and the hydrolysis rate is measured on addition of new enzyme. As summarized in Table 7, results from restart experiments have been used as a basis to both confirm (488,776) and reject (152,233,507) declining substrate reactivity as a primary factor responsible for the declining rate phenomenon. Gusakov et al (233) explain declining rates in terms of deactivation of substrate-bound cellulase and product inhibition.…”

Section: Rates Of Enzymatic Hydrolysismentioning

confidence: 95%

“…A near-universal feature of cellulose hydrolysis observed in many studies over several decades is that the rate declines sharply as the reaction proceeds (corresponding to increasing values of ) in a batch hydrolysis. Measurements of rate in conjunction with adsorbed enzyme (152,498,507) confirm that the phenomenon of declining rate with increasing conversion is observed on a specific (rate per adsorbed enzyme) as well as absolute basis. Enzyme inactivation due to thermal effects (91, 117, 219), formation of an inactive enzyme-substrate (lignin) complex (234,506,657), and inhibition by hydrolysis products (91,233,377) have been implicated as important factors underlying the decreasing-rate phenomenon.…”

Section: Rates Of Enzymatic Hydrolysismentioning

confidence: 99%

See 1 more Smart Citation

Microbial Cellulose Utilization: Fundamentals and Biotechnology

Lynd

Weimer

Zyl³

et al. 2002

Microbiol Mol Biol Rev

4,019

2,868

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Fundamental features of microbial cellulose utilization are examined at successively higher levels of aggregation encompassing the structure and composition of cellulosic biomass, taxonomic diversity, cellulase enzyme systems, molecular biology of cellulase enzymes, physiology of cellulolytic microorganisms, ecological aspects of cellulase-degrading communities, and rate-limiting factors in nature. The methodological basis for studying microbial cellulose utilization is considered relative to quantification of cells and enzymes in the presence of solid substrates as well as apparatus and analysis for cellulose-grown continuous cultures. Quantitative description of cellulose hydrolysis is addressed with respect to adsorption of cellulase enzymes, rates of enzymatic hydrolysis, bioenergetics of microbial cellulose utilization, kinetics of microbial cellulose utilization, and contrasting features compared to soluble substrate kinetics. A biological perspective on processing cellulosic biomass is presented, including features of pretreated substrates and alternative process configurations. Organism development is considered for “consolidated bioprocessing” (CBP), in which the production of cellulolytic enzymes, hydrolysis of biomass, and fermentation of resulting sugars to desired products occur in one step. Two organism development strategies for CBP are examined: (i) improve product yield and tolerance in microorganisms able to utilize cellulose, or (ii) express a heterologous system for cellulose hydrolysis and utilization in microorganisms that exhibit high product yield and tolerance. A concluding discussion identifies unresolved issues pertaining to microbial cellulose utilization, suggests approaches by which such issues might be resolved, and contrasts a microbially oriented cellulose hydrolysis paradigm to the more conventional enzymatically oriented paradigm in both fundamental and applied contexts

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Section: Rates Of Enzymatic Hydrolysismentioning

confidence: 95%

Section: Rates Of Enzymatic Hydrolysismentioning

confidence: 99%

Microbial Cellulose Utilization: Fundamentals and Biotechnology

Lynd

Weimer

Zyl³

et al. 2002

Microbiol Mol Biol Rev

4,019

2,868

View full text Add to dashboard Cite

show abstract

“…Restarting hydrolysis with fresh enzyme is an adequate experiment to measure the losses of substrate reactivity [35,[40][41][42]. It is still difficult to explain the decrease of the reaction rate vis a vis the evolution of morphological features of the substrate.…”

Section: Introductionmentioning

confidence: 92%

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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“…Moreover, the assumption of two kinds of cellulose present in substrate was contradicted by Ooshima et aI. (1991), Desai and Converse (1997), and Yang et al (2006). It was found that the reactivity of substrate did not change during hydrolysis.…”

Section: Cellulose Hydrolysismentioning

confidence: 99%

“…Moreover, this theory was contradicted by Ooshima et ai. (1991), Desai and Converse (1997), and Yang et al (2006), who all found that the reactivity of substrate changed little during hydrolysis. Also, the two-types of cellulose mechanism cannot explain the monophasic first-order reaction for some substrates such as cotton and regenerated cellulose (Lenz et aI., 1990;Schurz and Honel, 1989).…”

Section: Introductionmentioning

confidence: 99%

The impact of adsorbed cellulase inactivation on enzymatic hydrolysis kinetics.

Ye¹

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Substrate reactivity as a function of the extent of reaction in the enzymatic hydrolysis of lignocellulose

Cited by 79 publications

References 17 publications

Microbial Cellulose Utilization: Fundamentals and Biotechnology

Microbial Cellulose Utilization: Fundamentals and Biotechnology

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

The impact of adsorbed cellulase inactivation on enzymatic hydrolysis kinetics.

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