Mechanism of rate enhancement of wood fiber saccharification by cationic polyelectrolytes

Mora, Sabrina; J, Lu; Banerjee, Sujit

doi:10.1007/s10529-011-0647-z

Cited by 8 publications

(8 citation statements)

References 11 publications

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“…Binding constants for the control (without c‐PAM) compare well to those reported by Warren et al It is clear that the c‐PAM greatly increases the binding of enzyme to starch. A similar situation applies to the binding of cellulase to cellulose . Increasing sorption through use of c‐PAM has been reported in other applications; e.g., Wang et al showed that c‐PAM increased the sorption capacity of modified bentonite.…”

Section: Resultssupporting

confidence: 58%

“…Some aspects of cornstarch hydrolysis are strikingly similar to those obtained earlier for cellulose, which suggests a common mechanism. It was proposed that the c‐PAM accelerated cellulose hydrolysis through a “patching” mechanism through which it neutralized the negative charge of the fiber and reduced the repulsion experienced by the negatively charge cellulase . It seems likely that a similar mechanism applies to cornstarch.…”

Section: Resultsmentioning

confidence: 99%

“…A “patching” mechanism was proposed where the polymer attaches to and neutralizes the negatively charged substrate, thereby decreasing the repulsion experienced by the approaching negatively charged enzyme. Stronger enzyme‐substrate binding results . Patching is well‐established in the literature on fiber agglomeration and on water treatment .…”

Section: Introductionmentioning

confidence: 94%

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Cationic polyacrylamides increase the rate of liquefaction and hydrolysis of cornstarch

2012

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in Wiley Online Library (wileyonlinelibrary.com).Cationic polyacrylamides (c-PAMs) bind to starch granules and decrease the temperature for the onset of gelatinization by 8 C. c-PAM increases the binding of -amylase to cornstarch; the rate of cornstarch hydrolysis also increases. By analogy to previous work on the c-PAM promoted hydrolysis of cellulose, it is proposed that the polymer reduces the charge on the surface of starch through a charge-patch mechanism. Because both enzyme and substrate are negatively charged, the bound c-PAM reduces the charge repulsion experienced by the approaching enzyme, which leads to stronger enzyme-substrate binding and faster hydrolysis. Overall, the c-PAM reduces enzyme dose by up to 62% under the conditions used. There is a mirror image relationship between the viscosity of the medium and the hydrolysis rate, which allows optimization of these parameters with enzyme and c-PAM dosage. Low c-PAM levels increase viscosity by agglomerating the substrate, but the viscosity drops at higher c-PAM concentration.

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Section: Resultssupporting

confidence: 58%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 94%

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Cationic polyacrylamides increase the rate of liquefaction and hydrolysis of cornstarch

2012

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“…The authors also demonstrated that almost all the tested LSs with varied sulfonation degrees and molecular weights (MW) could enhance the enzymatic conversion of pre‐treated lignocellulose . Lu et al developed a ‘patching/bridging’ strategy based on cationic polyacrylamide (CPAM) to minimize the charge repulsion between fiber and enzyme by reducing their zeta potential on the particle surface. The authors demonstrated that CPAM indirectly promoted enzyme binding to the substrates and hence increased the rate of hydrolysis…”

Section: Strategies To Minimize Cellulase‐lignin Interactionsmentioning

confidence: 99%

Toward a fundamental understanding of cellulase‐lignin interactions in the whole slurry enzymatic saccharification process

Liu

Sun

Leu

et al. 2016

Biofuels Bioprod Bioref

130

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Lignocellulosic biomass is a promising feedstock for sustainable production of non‐food building‐block sugars. This bioconversion process is preferentially carried out through the whole slurry enzymatic saccharification of the pre‐treated lignocellulosic substrates. However, dissolved lignin, residual lignin, and lignin‐derived phenolic molecules in the pre‐treated biomass slurry can all trigger the decrease in activity and stability of cellulases, as well as the unfavorable enzyme recyclability. The hydrolyzing efficiencies can be considerably hindered by the lignin‐induced non‐productive binding of cellulases through various mechanisms. Three major non‐covalent forces, i.e., hydrophobic, electrostatic, and hydrogen bonds interactions, can occur between the amino acid residues in cellulases and the functional groups in lignin. Various strategies such as enzyme engineering, substrate modification, additive blocking have been intensively developed to minimize the cellulase‐lignin interactions. To investigate the impacts and benefits of different mechanisms and processes, this paper provides a systematic overview of the current opinions about the non‐productive binding of cellulase to lignin. Through better understanding of their interactions it is our hope that the enzyme binding groups in lignin could be properly quenched by using new pre‐treatment methods and/or biochemical processing strategies to increase the efficiency of cellulose bioconversion. © 2016 Society of Chemical Industry and John Wiley & Sons, Ltd

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“…Effect of chemical de-ashing (HCl wash), c-PAM addition (XP-[16][17][18][19][20], and H 2 O 2 pretreatment on ethanol yield, final ethanol titers, and rate of glucose consumption and ethanol production on different sludge tested during fermentation by FermPro yeast.…”

mentioning

confidence: 99%

Bioconversion of paper mill sludge to bioethanol in the presence of accelerants or hydrogen peroxide pretreatment

Gurram

Al-Shannag

Lecher

et al. 2015

Bioresource Technology

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In this study we investigated the technical feasibility of convert paper mill sludge into fuel ethanol. This involved the removal of mineral fillers by using either chemical pretreatment or mechanical fractionation to determine their effects on cellulose hydrolysis and fermentation to ethanol. In addition, we studied the effect of cationic polyelectrolyte (as accelerant) addition and hydrogen peroxide pretreatment on enzymatic hydrolysis and fermentation. We present results showing that removing the fillers content (ash and calcium carbonate) from the paper mill sludge increases the enzymatic hydrolysis performance dramatically with higher cellulose conversion at faster rates. The addition of accelerant and hydrogen peroxide pretreatment further improved the hydrolysis yields by 16% and 25% (g glucose / g cellulose), respectively with the de-ashed sludge. The fermentation process of produced sugars achieved up to 95% of the maximum theoretical ethanol yield and higher ethanol productivities within 9h of fermentation.

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Mechanism of rate enhancement of wood fiber saccharification by cationic polyelectrolytes

Cited by 8 publications

References 11 publications

Cationic polyacrylamides increase the rate of liquefaction and hydrolysis of cornstarch

Cationic polyacrylamides increase the rate of liquefaction and hydrolysis of cornstarch

Toward a fundamental understanding of cellulase‐lignin interactions in the whole slurry enzymatic saccharification process

Bioconversion of paper mill sludge to bioethanol in the presence of accelerants or hydrogen peroxide pretreatment

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