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.