BcsAB synthesized cellulose on nickel surface: polymerization of monolignols during cellulose synthesis alters cellulose morphology

Basu, Snehasish; Catchmark, Jeffrey M.; Brown, Nicole R.; Anderson, Charles T.; Górniak, Ireneusz

doi:10.1007/s10570-020-03178-7

Cited by 3 publications

(3 citation statements)

References 36 publications

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“…Lignocellulose samples were created by combining cellulose with coniferyl alcohol (CA), hydrogen peroxide, and horseradish peroxidase (HRP) to polymerize G-lignin on the cellulose surface (34). Two different methods were used to produce the lignin, the first used increasing (HRP) catalyst concentrations proportionally with the hydrogen peroxide and CA concentrations, and the second maintained a constant HRP concentration while the hydrogen peroxide and CA concentrations were increased.…”

Section: Cellulose and Lignin Preparation And Characterization -Bacte...mentioning

confidence: 99%

“…Here, we extended this singlemolecule fluorescence approach to test potential molecular mechanisms by which lignin inhibits cellulose degradation by Cel7A. Synthetic analogs of plant cell walls were constructed by polymerizing G-lignin in vitro onto bacterial cellulose at varying lignin-to-cellulose ratios (34). This approach eliminates potential effects of other wall components like hemicellulose and pectin, allowing us to focus only on lignin bound to cellulose.…”

Section: Introductionmentioning

confidence: 99%

“…Instead, the data indicate that lignin inhibits Cel7A by blocking its initial interaction with the cellulose surface and by impeding the progress of moving Cel7A molecules. To examine how lignin alters cellulose degradation by Cel7A, we created lignified cellulose by depositing lignin onto Acetobacter cellulose in vitro using a mixture of coniferyl alcohol, hydrogen peroxide and horseradish peroxidase (34). To vary the degree of lignification, the reaction contained 4.25 mM cellulose and between 0.11 mM and 9 mM coniferyl alcohol and hydrogen peroxide.…”

Section: Introductionmentioning

confidence: 99%

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Lignin impairs Cel7A degradation of cellulose by impeding enzyme movement and not by acting as a sink

Haviland,

Nong,

Zexer

et al. 2023

Preprint

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Background: Cellulose degradation by cellulases has been studied for decades due to the potential of using lignocellulosic biomass as a sustainable source of bioethanol. In plant cell walls, cellulose is bonded together and strengthened by the polyphenolic polymer, lignin. Because lignin is tightly linked to cellulose and is not digestible by cellulases, is thought to play a dominant role in limiting the efficient enzymatic degradation of plant biomass. Removal of lignin via pretreatments currently limits the cost-efficient production of ethanol from cellulose, motivating the need for a better understanding of how lignin inhibits cellulase-catalyzed degradation of lignocellulose. Work to date using bulk assays has suggested three possible inhibition mechanisms: lignin blocks access of the enzyme to cellulose, lignin impedes progress of the enzyme along cellulose, or lignin binds cellulases directly and acts as a sink. Results: We used single-molecule fluorescence microscopy to investigate the nanoscale dynamics of Cel7A from Trichoderma reesei, as it binds to and moves along purified bacterial cellulose in vitro. Lignified cellulose was generated by polymerizing coniferyl alcohol onto purified bacterial cellulose, and the degree of lignin incorporation into the cellulose meshwork was analyzed by optical and electron microscopy. We found that Cel7A preferentially bound to regions of cellulose where lignin was absent, and that in regions of high lignin density, Cel7A binding was inhibited. With increasing degrees of lignification, there was a decrease in the fraction of Cel7A that moved along cellulose rather than statically binding. Furthermore, with increasing lignification, the velocity of processive Cel7A movement decreased, as did the distance that individual Cel7A molecules moved during processive runs. Conclusions: In an in vitro system that mimics lignified cellulose in plant cell walls, lignin did not act as a sink to sequester Cel7A and prevent it from interacting with cellulose. Instead, lignin both blocked access of Cel7A to cellulose and impeded the processive movement of Cel7A along cellulose. This work implies that strategies for improving biofuel production efficiency should target weakening interactions between lignin and cellulose surface, and further suggest that nonspecific adsorption of Cel7A to lignin is likely not a dominant mechanism of inhibition.

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Section: Cellulose and Lignin Preparation And Characterization -Bacte...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Lignin impairs Cel7A degradation of cellulose by impeding enzyme movement and not by acting as a sink

Haviland,

Nong,

Zexer

et al. 2023

Preprint

Self Cite

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Catalytic conversion of levulinic acid or furfural alcohol into ethyl levulinate using a sulfonic acid-functionalized coffee biochar

Gong,

Zhang,

et al. 2023

Fuel

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Lignin impairs Cel7A degradation of in vitro lignified cellulose by impeding enzyme movement and not by acting as a sink

Haviland,

Nong,

Zexer

et al. 2024

Biotechnol Biofuels

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Background Cellulose degradation by cellulases has been studied for decades due to the potential of using lignocellulosic biomass as a sustainable source of bioethanol. In plant cell walls, cellulose is bonded together and strengthened by the polyphenolic polymer, lignin. Because lignin is tightly linked to cellulose and is not digestible by cellulases, is thought to play a dominant role in limiting the efficient enzymatic degradation of plant biomass. Removal of lignin via pretreatments currently limits the cost-efficient production of ethanol from cellulose, motivating the need for a better understanding of how lignin inhibits cellulase-catalyzed degradation of lignocellulose. Work to date using bulk assays has suggested three possible inhibition mechanisms: lignin blocks access of the enzyme to cellulose, lignin impedes progress of the enzyme along cellulose, or lignin binds cellulases directly and acts as a sink. Results We used single-molecule fluorescence microscopy to investigate the nanoscale dynamics of Cel7A from Trichoderma reesei, as it binds to and moves along purified bacterial cellulose in vitro. Lignified cellulose was generated by polymerizing coniferyl alcohol onto purified bacterial cellulose, and the degree of lignin incorporation into the cellulose meshwork was analyzed by optical and electron microscopy. We found that Cel7A preferentially bound to regions of cellulose where lignin was absent, and that in regions of high lignin density, Cel7A binding was inhibited. With increasing degrees of lignification, there was a decrease in the fraction of Cel7A that moved along cellulose rather than statically binding. Furthermore, with increasing lignification, the velocity of processive Cel7A movement decreased, as did the distance that individual Cel7A molecules moved during processive runs. Conclusions In an in vitro system that mimics lignified cellulose in plant cell walls, lignin did not act as a sink to sequester Cel7A and prevent it from interacting with cellulose. Instead, lignin both blocked access of Cel7A to cellulose and impeded the processive movement of Cel7A along cellulose. This work implies that strategies for improving biofuel production efficiency should target weakening interactions between lignin and cellulose surface, and further suggest that nonspecific adsorption of Cel7A to lignin is likely not a dominant mechanism of inhibition.

show abstract

BcsAB synthesized cellulose on nickel surface: polymerization of monolignols during cellulose synthesis alters cellulose morphology

Cited by 3 publications

References 36 publications

Lignin impairs Cel7A degradation of cellulose by impeding enzyme movement and not by acting as a sink

Lignin impairs Cel7A degradation of cellulose by impeding enzyme movement and not by acting as a sink

Catalytic conversion of levulinic acid or furfural alcohol into ethyl levulinate using a sulfonic acid-functionalized coffee biochar

Lignin impairs Cel7A degradation of in vitro lignified cellulose by impeding enzyme movement and not by acting as a sink

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