Heterologous co-expression of two β-glucanases and a cellobiose phosphorylase resulted in a significant increase in the cellulolytic activity of the Caldicellulosiruptor bescii exoproteome

  • Sun-Ki Kim
  • Daehwan Chung
  • Michael E. Himmel
  • Yannick J. Bomble
  • Janet WestphelingEmail author
Bioenergy/Biofuels/Biochemicals - Original Paper


The ability to deconstruct plant biomass without conventional pretreatment has made members of the genus Caldicellulosiruptor the target of investigation for the consolidated processing of plant lignocellulosic biomass to biofuels and bioproducts. To investigate the synergy of enzymes involved and to further improve the ability of C. bescii to degrade cellulose, we introduced CAZymes that act synergistically with the C. bescii exoproteome in vivo and in vitro. We recently demonstrated that the Acidothermus cellulolyticus E1 endo-1,4-β-D-glucanase (GH5) with a family 2 carbohydrate-binding module (CBM) increased the activity of C. bescii exoproteome on biomass, presumably acting in concert with CelA. The β-glucanase, GuxA, from A. cellulolyticus is a multi-domain enzyme with strong processive exoglucanase activity, and the cellobiose phosphorylase from Thermotoga maritima catalyzes cellulose degradation acting synergistically with cellobiohydrolases and endoglucanases. We identified new chromosomal insertion sites to co-express these enzymes and the resulting strain showed a significant increase in the enzymatic activity of the exoproteome.


Consolidated bioprocessing Biomass deconstruction Glucanase Cellobiose phosphorylase Gene integration Caldicellulosiruptor 



We thank Jordan Russell and Theodoric Mattes for critical review of the Manuscript and Shreena Patel for technical assistance. This work was supported by the BioEnergy Science Center and the Center for BioEnergy Innovation, US DOE Office of Biological and Environmental Research in the DOE Office of Science. Oak Ridge National Laboratory is managed by UT-Battelle, LLC, for the US DOE under contract DE-AC05-00OR22725. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Supplementary material

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Supplementary material 1 (DOCX 14 kb)


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Copyright information

© Society for Industrial Microbiology and Biotechnology 2019

Authors and Affiliations

  • Sun-Ki Kim
    • 1
    • 2
    • 4
  • Daehwan Chung
    • 3
    • 4
  • Michael E. Himmel
    • 3
    • 4
  • Yannick J. Bomble
    • 3
    • 4
  • Janet Westpheling
    • 1
    • 4
    Email author
  1. 1.Department of GeneticsUniversity of GeorgiaAthensUSA
  2. 2.Department of Food Science and TechnologyChung-Ang UniversityAnseongRepublic of Korea
  3. 3.Biosciences Center, National Renewable Energy LaboratoryGoldenUSA
  4. 4.The BioEnergy Science Center and the Center for BioEnergy InnovationOak Ridge National LaboratoryOak RidgeUSA

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