Biorefining of softwoods using ethanol organosolv pulping: Preliminary evaluation of process streams for manufacture of fuel-grade ethanol and co-products

Authors

  • Xuejun Pan,

    Corresponding author
    1. Forest Products Biotechnology, Department of Wood Science, University of British Columbia, 2424 Main Mall, Vancouver, B.C., Canada, V6T 1Z4; telephone: 604-822-6775; fax: 604-822-9104
    • Forest Products Biotechnology, Department of Wood Science, University of British Columbia, 2424 Main Mall, Vancouver, B.C., Canada, V6T 1Z4; telephone: 604-822-6775; fax: 604-822-9104
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  • Claudio Arato,

    1. Lignol Innovations, 3650 Wesbrook Mall, Vancouver, BC, Canada, V6S 2L2
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  • Neil Gilkes,

    1. Forest Products Biotechnology, Department of Wood Science, University of British Columbia, 2424 Main Mall, Vancouver, B.C., Canada, V6T 1Z4; telephone: 604-822-6775; fax: 604-822-9104
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  • David Gregg,

    1. Forest Products Biotechnology, Department of Wood Science, University of British Columbia, 2424 Main Mall, Vancouver, B.C., Canada, V6T 1Z4; telephone: 604-822-6775; fax: 604-822-9104
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  • Warren Mabee,

    1. Forest Products Biotechnology, Department of Wood Science, University of British Columbia, 2424 Main Mall, Vancouver, B.C., Canada, V6T 1Z4; telephone: 604-822-6775; fax: 604-822-9104
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  • Kendall Pye,

    1. Lignol Innovations, 3650 Wesbrook Mall, Vancouver, BC, Canada, V6S 2L2
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  • Zhizhuang Xiao,

    1. Forest Products Biotechnology, Department of Wood Science, University of British Columbia, 2424 Main Mall, Vancouver, B.C., Canada, V6T 1Z4; telephone: 604-822-6775; fax: 604-822-9104
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  • Xiao Zhang,

    1. Forest Products Biotechnology, Department of Wood Science, University of British Columbia, 2424 Main Mall, Vancouver, B.C., Canada, V6T 1Z4; telephone: 604-822-6775; fax: 604-822-9104
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  • John Saddler

    1. Forest Products Biotechnology, Department of Wood Science, University of British Columbia, 2424 Main Mall, Vancouver, B.C., Canada, V6T 1Z4; telephone: 604-822-6775; fax: 604-822-9104
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Abstract

Pulps with residual lignin ranging from 6.4–27.4% (w/w) were prepared from mixed softwoods using a proprietary biorefining technology (the Lignol process) based on aqueous ethanol organosolv extraction. The pulps were evaluated for bioconversion using enzymatic hydrolysis of the cellulose fraction to glucose and subsequent fermentation to ethanol. All pulps were readily hydrolyzed without further delignification. More than 90% of the cellulose in low lignin pulps (≤18.4% residual lignin) was hydrolyzed to glucose in 48 h using an enzyme loading of 20 filter paper units/g cellulose. Cellulose in a high lignin pulp (27.4% residual lignin) was hydrolyzed to >90% conversion within 48 h using 40 filter paper units/g. The pulps performed well in both sequential and simultaneous saccharification and fermentation trials indicating an absence of metabolic inhibitors. Chemical and physical analyses showed that lignin extracted during organosolv pulping of softwood is a suitable feedstock for production of lignin-based adhesives and other products due to its high purity, low molecular weight, and abundance of reactive groups. Additional co-products may be derived from the hemicellulose sugars and furfural recovered from the water-soluble stream. © 2005 Wiley Periodicals, Inc.

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