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Title: Nanomechanics of cellulose deformation reveal molecular defects that facilitate natural deconstruction

Abstract

Technologies surrounding utilization of cellulosic materials have been integral to human society for millennia. In many materials, controlled introduction of defects provides a means to tailor properties, introduce reactivity, and modulate functionality for various applications. The importance of defects in defining the behavior of cellulose is becoming increasingly recognized. However, fully exploiting defects in cellulose to benefit biobased materials and conversion applications will require an improved understanding of the mechanisms of defect induction and corresponding molecular-level consequences. We have identified a fundamental relationship between the macromolecular structure and mechanical behavior of cellulose nanofibrils whereby molecular defects may be induced when the fibrils are subjected to bending stress exceeding a certain threshold. By nanomanipulation, imaging, and molecular modeling, we demonstrate that cellulose nanofibrils tend to form kink defects in response to bending stress, and that these macromolecular features are often accompanied by breakages in the glucan chains. Direct observation of deformed cellulose fibrils following partial enzymatic digestion reveals that processive cellulases exploit these defects as initiation sites for hydrolysis. Collectively, our findings provide a refined understanding of the interplay between the structure, mechanics, and reactivity of cellulose assemblies.

Authors:
ORCiD logo [1];  [2]; ORCiD logo [1];  [2];  [1]; ORCiD logo [1]; ORCiD logo [1];  [1];  [1]
  1. National Renewable Energy Lab. (NREL), Golden, CO (United States)
  2. National Inst. of Standards and Technology (NIST), Boulder, CO (United States)
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1512662
Alternate Identifier(s):
OSTI ID: 1509915
Report Number(s):
NREL/JA-2700-73748
Journal ID: ISSN 0027-8424
Grant/Contract Number:  
AC36-08GO28308
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Journal Volume: 116; Journal Issue: 20; Journal ID: ISSN 0027-8424
Publisher:
National Academy of Sciences, Washington, DC (United States)
Country of Publication:
United States
Language:
English
Subject:
09 BIOMASS FUELS; cellulose; cellulases; atomic force microscopy; molecular dynamics; quantum mechanics

Citation Formats

Ciesielski, Peter N., Wagner, Ryan, Bharadwaj, Vivek S., Killgore, Jason, Mittal, Ashutosh, Beckham, Gregg T., Decker, Steve, Himmel, Michael E., and Crowley, Michael F. Nanomechanics of cellulose deformation reveal molecular defects that facilitate natural deconstruction. United States: N. p., 2019. Web. doi:10.1073/pnas.1900161116.
Ciesielski, Peter N., Wagner, Ryan, Bharadwaj, Vivek S., Killgore, Jason, Mittal, Ashutosh, Beckham, Gregg T., Decker, Steve, Himmel, Michael E., & Crowley, Michael F. Nanomechanics of cellulose deformation reveal molecular defects that facilitate natural deconstruction. United States. doi:10.1073/pnas.1900161116.
Ciesielski, Peter N., Wagner, Ryan, Bharadwaj, Vivek S., Killgore, Jason, Mittal, Ashutosh, Beckham, Gregg T., Decker, Steve, Himmel, Michael E., and Crowley, Michael F. Mon . "Nanomechanics of cellulose deformation reveal molecular defects that facilitate natural deconstruction". United States. doi:10.1073/pnas.1900161116. https://www.osti.gov/servlets/purl/1512662.
@article{osti_1512662,
title = {Nanomechanics of cellulose deformation reveal molecular defects that facilitate natural deconstruction},
author = {Ciesielski, Peter N. and Wagner, Ryan and Bharadwaj, Vivek S. and Killgore, Jason and Mittal, Ashutosh and Beckham, Gregg T. and Decker, Steve and Himmel, Michael E. and Crowley, Michael F.},
abstractNote = {Technologies surrounding utilization of cellulosic materials have been integral to human society for millennia. In many materials, controlled introduction of defects provides a means to tailor properties, introduce reactivity, and modulate functionality for various applications. The importance of defects in defining the behavior of cellulose is becoming increasingly recognized. However, fully exploiting defects in cellulose to benefit biobased materials and conversion applications will require an improved understanding of the mechanisms of defect induction and corresponding molecular-level consequences. We have identified a fundamental relationship between the macromolecular structure and mechanical behavior of cellulose nanofibrils whereby molecular defects may be induced when the fibrils are subjected to bending stress exceeding a certain threshold. By nanomanipulation, imaging, and molecular modeling, we demonstrate that cellulose nanofibrils tend to form kink defects in response to bending stress, and that these macromolecular features are often accompanied by breakages in the glucan chains. Direct observation of deformed cellulose fibrils following partial enzymatic digestion reveals that processive cellulases exploit these defects as initiation sites for hydrolysis. Collectively, our findings provide a refined understanding of the interplay between the structure, mechanics, and reactivity of cellulose assemblies.},
doi = {10.1073/pnas.1900161116},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
issn = {0027-8424},
number = 20,
volume = 116,
place = {United States},
year = {2019},
month = {4}
}

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Works referenced in this record:

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