Strength of adsorption of polyethylene glycol on pretreated Pinus radiata wood and consequences for enzymatic saccharification

Vaidya, Alankar A.; Newman, Roger H.; Campion, Sylke H.; Suckling, Ian D.

doi:10.1016/j.biombioe.2014.08.024

Cited by 28 publications

(24 citation statements)

References 29 publications

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“…Based on these information, the important loss in fluorescence observed in the SE samples can be attributed to one or several of the following causes: decrease of lignin content; alteration of linkages between monolignols making lignin; modification of the cross-linkages between lignin and hemicellulose and of the organization of the polymers (mainly cellulose and hemicellulose) surrounding lignin. If SE samples fluorescence was expected to be mainly influenced by the packing polymers around lignin, a possible approach could be to assay the lignin chemical and physical accessibility in the pretreated samples 39 , 40 , but since samples were “exploded” after pretreatment, these techniques could not be applied. Previously, an in-depth chemical analysis of the same pretreated samples was performed.…”

Section: Discussionmentioning

confidence: 99%

Seeing biomass recalcitrance through fluorescence

Auxenfans

Terryn

Paës

2017

Sci Rep

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Lignocellulosic biomass is the only renewable carbon resource available in sufficient amount on Earth to go beyond the fossil-based carbon economy. Its transformation requires controlled breakdown of polymers into a set of molecules to make fuels, chemicals and materials. But biomass is a network of various inter-connected polymers which are very difficult to deconstruct optimally. In particular, saccharification potential of lignocellulosic biomass depends on several complex chemical and physical factors. For the first time, an easily measurable fluorescence properties of steam-exploded biomass samples from miscanthus, poplar and wheat straw was shown to be directly correlated to their saccharification potential. Fluorescence can thus be advantageously used as a predictive method of biomass saccharification. The loss in fluorescence occurring after the steam explosion pretreatment and increasing with pretreatment severity does not originate from the loss in lignin content, but rather from a decrease of the lignin β-aryl-ether linkage content. Fluorescence lifetime analysis demonstrates that monolignols making lignin become highly conjugated after steam explosion pretreatment. These results reveal that lignin chemical composition is a more important feature to consider than its content to understand and to predict biomass saccharification.

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Section: Discussionmentioning

confidence: 99%

Seeing biomass recalcitrance through fluorescence

Auxenfans

Terryn

Paës

2017

Sci Rep

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“…Two key amino acids, Tyr 171 and Asn 184, contributed to CBHI activity enhancement by PEG . On the lignin‐blocking function, the binding constant of PEG on pre‐treated biomass was 10‐times higher than the constant for cellulase‐lignin binding . However, PEG chemicals show minimal effect on EG and BG…”

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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“…This is confirmed by the measurement of interaction forces by atomic force microscopy: interactions are stronger between cellulases and lignin than between cellulase and cellulose [ 11 ]. Microscopic observations using PEG have demonstrated that solvent-exposed lignin is likely to be responsible for non-productive binding of enzymes [ 12 ] so that addition of PEG during saccharification increases glucose yields [ 13 ] by keeping cellulases free. Different spectroscopic analysis, surface accessibility, and adsorption measurements have been carried out to correlate the presence of chemical motifs belonging to different biomass samples with the binding of enzymes [ 14 , 15 ], but data are difficult to interpret.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the binding properties of a multi-modular GH45 cellulase using bioinspired model assemblies

Fong

Berrin

Paës

2016

Biotechnol Biofuels

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BackgroundEnzymes degrading plant biomass polymers are widely used in biotechnological applications. Their efficiency can be limited by non-specific interactions occurring with some chemical motifs. In particular, the lignin component is known to bind enzymes irreversibly. In order to determine interactions of enzymes with their substrates, experiments are usually performed on isolated simple polymers which are not representative of plant cell wall complexity. But when using natural plant substrates, the role of individual chemical and structural features affecting enzyme-binding properties is also difficult to decipher.ResultsWe have designed and used lignified model assemblies of plant cell walls as templates to characterize binding properties of multi-modular cellulases. These three-dimensional assemblies are modulated in their composition using the three principal polymers found in secondary plant cell walls (cellulose, hemicellulose, and lignin). Binding properties of enzymes are obtained from the measurement of their mobility that depends on their interactions with the polymers and chemical motifs of the assemblies. The affinity of the multi-modular GH45 cellulase was characterized using a statistical analysis to determine the role played by each assembly polymer. Presence of hemicellulose had much less impact on affinity than cellulose and model lignin. Depending on the number of CBMs appended to the cellulase catalytic core, binding properties toward cellulose and lignin were highly contrasted.ConclusionsModel assemblies bring new insights into the molecular determinants that are responsible for interactions between enzymes and substrate without the need of complex analysis. Consequently, we believe that model bioinspired assemblies will provide relevant information for the design and optimization of enzyme cocktails in the context of biorefineries.Electronic supplementary materialThe online version of this article (doi:10.1186/s13068-016-0428-y) contains supplementary material, which is available to authorized users.

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Strength of adsorption of polyethylene glycol on pretreated Pinus radiata wood and consequences for enzymatic saccharification

Cited by 28 publications

References 29 publications

Seeing biomass recalcitrance through fluorescence

Seeing biomass recalcitrance through fluorescence

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

Investigation of the binding properties of a multi-modular GH45 cellulase using bioinspired model assemblies

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