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Title: The Multi Domain Caldicellulosiruptor bescii CelA Cellulase Excels at the Hydrolysis of Crystalline Cellulose

The crystalline nature of cellulose microfibrils is one of the key factors influencing biomass recalcitrance which is a key technical and economic barrier to overcome to make cellulosic biofuels a commercial reality. To date, all known fungal enzymes tested have great difficulty degrading highly crystalline cellulosic substrates. We have demonstrated that the CelA cellulase from Caldicellulosiruptor bescii degrades highly crystalline cellulose as well as low crystallinity substrates making it the only known cellulase to function well on highly crystalline cellulose. Unlike the secretomes of cellulolytic fungi, which typically comprise multiple, single catalytic domain enzymes for biomass degradation, some bacterial systems employ an alternative strategy that utilizes multi-catalytic domain cellulases. Additionally, CelA is extremely thermostable and highly active at elevated temperatures, unlike commercial fungal cellulases. Furthermore we have determined that the factors negatively affecting digestion of lignocellulosic materials by C. bescii enzyme cocktails containing CelA appear to be significantly different from the performance barriers affecting fungal cellulases. Furthermore, we explore the activity and degradation mechanism of CelA on a variety of pretreated substrates to better understand how the different bulk components of biomass, such as xylan and lignin, impact its performance.
Authors:
 [1] ; ORCiD logo [1] ;  [1] ;  [1] ; ORCiD logo [2] ;  [2] ;  [1] ;  [3] ;  [1] ;  [3] ;  [2] ;  [1] ;  [1]
  1. National Renewable Energy Lab. (NREL), Golden, CO (United States)
  2. Novozymes, Inc., Davis, CA (United States)
  3. Univ. of Georgia, Athens, GA (United States)
Publication Date:
Report Number(s):
NREL/JA-2700-68492
Journal ID: ISSN 2045-2322
Grant/Contract Number:
AC36-08GO28308
Type:
Accepted Manuscript
Journal Name:
Scientific Reports
Additional Journal Information:
Journal Volume: 7; Journal Issue: 1; Journal ID: ISSN 2045-2322
Publisher:
Nature Publishing Group
Research Org:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Building Technologies Office (EE-5B)
Country of Publication:
United States
Language:
English
Subject:
09 BIOMASS FUELS; cellulosic biofuels; biomass; recalcitrance
OSTI Identifier:
1389737