Degradation of Crystalline Celluloses by <I>Phanerochaete chrysosporium </I>Cellobiohydrolase II (Cel6A) Heterologously Expressed in Methylotrophic Yeast <I>Pichia pastoris</I>

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Author(s)

    • Igarashi Kiyohiko
    • Department of Biomaterial Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo
    • Maruyama Michiko
    • Department of Biomaterial Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo
    • Nakamura Akihiko
    • Department of Biomaterial Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo
    • Ishida Takuya
    • Department of Biomaterial Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo
    • Wada Masahisa
    • Department of Biomaterial Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo|Department of Plant & Environmental New Resources, College of Life Sciences, Kyung Hee University
    • Samejima Masahiro
    • Department of Biomaterial Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo

Abstract

Hydrolysis of crystalline cellulose is a crucial step in utilization of cellulosic biomass and is generally the bottleneck in the biochemical process. The combination of pre-treatment and the use of suitable enzymes is the key to effective saccharification, and ammonia pretreatment is a promising technique to enhance the velocity and yield in saccharification of crystalline cellulose. In the present study, we heterologously expressed recombinant cellobiohydrolase II from <I>Phanerochaete chrysosporium </I>(<I>Pc</I>Cel6A) in <I>Pichia pastoris</I>. We then employed surface density analysis to compare the velocities of degradation of crystalline cellulose III<SUB>I</SUB>, which was prepared from algal cellulose I by supercritical ammonia treatment, by the recombinant enzyme and <I>Trichoderma reesei </I>cellobiohydrolase I (<I>Tr</I>Cel7A). The hydrolytic velocity of crystalline cellulose III<SUB>I</SUB> by <I>Pc</I>Cel6A was approximately 4 times faster than that by <I>Tr</I>Cel7A, though velocity of cellulose I degradation by <I>Pc</I>Cel6A was almost half of that by <I>Tr</I>Cel7A. Since adsorption of both enzymes on cellulose III<SUB>I</SUB> is no more than twice that on cellulose I, we speculate that the enhanced hydrolysis of cellulose III<SUB>I</SUB> by <I>Pc</I>Cel6A than <I>Tr</I>Cel7A is not simply due to the increased surface area, but also reflects higher accessibility of cellulose III<SUB>I</SUB> to <I>Pc</I>Cel6A.

Journal

  • Journal of Applied Glycoscience

    Journal of Applied Glycoscience 59(3), 105-110, 2012

    The Japanese Society of Applied Glycoscience

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