Applied Biochemistry and Biotechnology

, Volume 78, Issue 1–3, pp 435–444 | Cite as

Bioconversion of secondary fiber fines to ethanol using counter-current enzymatic saccharification and Co-fermentation

  • Thomas W. JeffriesEmail author
  • Richard Schartman


This research examined several enzymatic and microbial process for the conversion of waste cellulosic fibers into ethanol. The first was a one-stage process in which pulp fines were contacted with commercial enzyme solutions. The second process used sequential, multistage saccharification. The third used sequential enzyme addition in a countercurrent mode. Experiments compared the results with various feed stocks, different commercial enzymes, supplementation with β-glucosidase, and saccharification combined with fermentation. The highest saccharification (65%) from a 4% consistency pulp and the highest sugar concentration (5.4%) from an 8% consistency pulp were attained when 5 FPU/g plus 10 IU/g of β-glucosidase were used. Sequential addition of enzyme to the pulp in small aliquots produced a higher overall sugar yield/U enzyme than the addition of the same total amount of enzyme in a singledose. In the saccharification and fermentation experiments, we produced 2.12% ethanol from a 5.4% sugar solution. This represents 78% of the theoretical maximum. This yield could probably be increased through optimization of the fermentation step. Even when little saccharification occurred, the enzyme facilitated separation of water, fiber, and ash, so cellulase treatment could be an effective means for dewatering pulp sludges.

Index Entries

Cellulase secondary fiber fines bioconversion 


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  1. 1.
    McGovern, J. N., Berbee, J. G., Bockhelm, J. G., and Baker, A. J. (1983), Tappi. J. 66(3), 115–118.Google Scholar
  2. 2.
    Joyce, T. W., Webb, A. A. and Dugal, H. S. (1979), Tappi. J. 62(4), 83–84.Google Scholar
  3. 3.
    Diehn, K. and Zuercher, B. (1990), Tappi. J. 73(4), 81–86.Google Scholar
  4. 4.
    Walkinshaw, J. W., Sladek, K. J., and Eberiel, D. T., (1984), Tappi. J. 67(10), 104–105.Google Scholar
  5. 5.
    Wayman, M., Chen, S., and Doan, K. (1992), Proc. Biochem. 27, 239–245.CrossRefGoogle Scholar
  6. 6.
    Jeffries, T. W., Yang, V., and Davies, M. (1998), Appl. Biochem. Biotechnol. 70/72, 257–265.Google Scholar
  7. 7.
    Miller, G. L. (1959), Anal. Chem. 31, 426–429.CrossRefGoogle Scholar
  8. 8.
    Jeffries, T. W. (1985), in Energy Applications of Biomass, Lowenstein, M. Z., ed., Elsevier, London and New York, pp. 231–251.Google Scholar

Copyright information

© Humana Press Inc. 1999

Authors and Affiliations

  1. 1.Forest Products LaboratoryUSDA, Forest ServiceMadison

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