Conclusions
The purpose of this study was to further elucidate the role of the
non-catalytic domains by designing a series of truncation mutants and
analyzing their ability to bind to and hydrolyze a variety of
substrates. The results of this study suggest that the CBMs play broadly
different roles in the cellulose degradation process, both in terms of
their binding specificity and enhancement of enzyme activity. CBMs are
characterized as having both targeting and disruptive functions on
different types of substrates. The presence and interaction of these CBM
modalities with cellulose may represent the requirement of different
binding properties that come into play during various states of cell
wall disruption. The observation that removal of CBM4 improved Cel9B’s
ability to degrade recalcitrant cellulose could potentially be used to
engineer this cellulase in the future with improved industrial
characteristics. The information gathered from this study will thus be
useful for the further understanding of how cellulases in general are
able to break down recalcitrant cellulose and will improve our knowledge
regarding how microbial cellulases can be utilized more effectively in
the future for the development of biofuel.
Ethics approval and consent to participate : Not applicableConsent for publication: The authors consent to the publication
of this manuscriptAvailability of data and material: Not applicableCompeting interests: The authors declare that they have no
competing interestsFunding: This work was supported by the BioEnergy Science
Center, a U.S. Department of Energy (DOE) center supported by the Office
of Biological and Environmental Research in the DOE Office of Science.Authors’ contributions: All authors contributed to the research
presented in this manuscript. The manuscript was written by Kathleen
Hefferon.Acknowledgements: The authors wish to acknowledge the work to
the memory of Dr. David Wilson, who is now deceased.