Abstract
Pretreatment of Douglas-fir by steam explosion produces a substrate containing approx 43% lignin. Two strategies were investigated for reducing the effect of this residual lignin on enzymatic hydrolysis of cellulose: mild alkali extraction and protein addition. Extraction with cold 1% NaOH reduced the lignin content by only approx 7%, but cellulose to glucose conversion was enhanced by about 30%. Before alkali extraction, addition of exogenous protein resulted in a significant improvement in cellulose hydrolysis, but this protein effect was substantially diminished after alkali treatment. Lignin appears to reduce cellulose hydrolysis by two distinct mechanisms: by forming a physical barrier that prevents enzyme access and by non-productively binding cellulolytic enzymes. Cold alkali appears to selectively remove a fraction of lignin from steam-exploded Douglas-fir with high affinity for protein. Corresponding data for mixed softwood pretreated by organosolv extraction indicates that the relative importance of the two mechanisms by which residual lignin affects hydrolysis is different according to the pre- and post-treatment method used.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
Galbe, M. and Zacchi, G. (2002), Appl. Microbiol. Biotechnol. 59, 618–628.
Wu, M. M., Chang, K., Gregg, D. J., Boussaid, A., Beatson, R. P., and Saddler, J. N. (1999), Appl. Biochem. Biotechnol. 77–79, 47–54.
BW McCloy & Associates, I. (2003), Estimated production, consumption and surplus mill residues in British Columbia, a 2003 update. Prepared for Natural Resources Canada.
Clark, T. A. and Mackie, K. L. (1987), J. Wood Chem. Technol. 7, 373–403.
Ramos, L. P., Breuil, C, and Saddler, J. N. (1992), Appl. Biochem. Biotechnol. 34–35, 37–48.
Tengborg, C, Stenberg, K., Galbe, M., et al. (1998), Appl. Biochem. Biotechnol. 70–72, 3–15.
Boussaid, A., Esteghlalian, A. R., Gregg, D. J., Lee, K. H. and Saddler, J. N. (2000), Appl. Biochem. Biotechnol. 84–86, 693–705.
Yang, B., Boussaid, A., Mansfield, S. D., Gregg, D. J., and Saddler, J. N. (2002), Biotechnol. Bioeng. 77, 678–684.
Pan, X. J., Zhang, X., Gregg, D. J., and Saddler, J. N. (2004), Appl. Biochem. Biotechnol. 113–116, 1103–1114.
Pan, X. J., Arato, C, Gilkes, N. R., et al. (2004), Biotechnol.Bioeng. in press.
Ghose, T. K. (1987), Pure Appl. Chem. 59, 257–268.
Wood, T. M. and Bhat, M. (1988), in Methods in Enzymology, Vol. 160, Biomass (Part A, Cellulose and Hemicellulose) (Colowick, S.P. and Kaplan, N.O., eds.). Academic Press, Inc., New York, pp. 87–112.
Dence, C. W. (1992), in Methods in Lignin Chemistry, Lin, S. Y. and Dence, C. W., eds., Springer-Verlag, Berlin, pp. 33–61.
Lai, Y.-Z. (1992), In: Methods in Lignin Chemistry, Lin, S. Y. and Dence, C. W., eds., Springer-Verlag, Berlin, pp. 423–434.
Montane, D., Farriol, X., Salvado, J., Jollez, P., and Chornet, E. (1998), J. Wood Chem. Technol. 18, 171–191.
Montane, D., Salvado, J., and Farriol, X. (1997), Holzforschung 51, 135–141.
Zimbardi, R, Viggiano, D., Nanna, R, Demichele, M., Cuna, D., and Cardinale, G. (1999), Appl. Biochem. Biotechnol. 77–79, 117–125.
Shevchenko, S. M., Beatson, R. P., and Saddler, J. N. (1999), Appl. Biochem. Biotechnol. 77–79, 867–876.
Sewalt, V. J. H., Glasser, W. G., and Beauchemin, K. A. (1997), J. Agricul. Food Chem. 45, 1823–1828.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2005 Humana Press Inc.
About this chapter
Cite this chapter
Pan, X., Xie, D., Gilkes, N., Gregg, D.J., Saddler, J.N. (2005). Strategies to Enhance the Enzymatic Hydrolysis of Pretreated Softwood with High Residual Lignin Content. In: Davison, B.H., Evans, B.R., Finkelstein, M., McMillan, J.D. (eds) Twenty-Sixth Symposium on Biotechnology for Fuels and Chemicals. ABAB Symposium. Humana Press. https://doi.org/10.1007/978-1-59259-991-2_90
Download citation
DOI: https://doi.org/10.1007/978-1-59259-991-2_90
Publisher Name: Humana Press
Print ISBN: 978-1-58829-697-9
Online ISBN: 978-1-59259-991-2
eBook Packages: Biomedical and Life SciencesBiomedical and Life Sciences (R0)