Get access

Tuning structural durability of yeast-encapsulating alginate gel beads with interpenetrating networks for sustained bioethanol production

Authors

  • Chaenyung Cha,

    1. Department of Chemistry, University of Illinois, Urbana, Illinois
    Search for more papers by this author
  • Soo Rin Kim,

    1. Department of Food Science and Human Nutrition, University of Illinois, Urbana, Illinois; telephone: +1-217-333-7981; fax: +1-217-333-0508 (Y.S.J.)
    Search for more papers by this author
  • Yong-Su Jin,

    Corresponding author
    1. Department of Food Science and Human Nutrition, University of Illinois, Urbana, Illinois; telephone: +1-217-333-7981; fax: +1-217-333-0508 (Y.S.J.)
    • Department of Food Science and Human Nutrition, University of Illinois, Urbana, Illinois; telephone: +1-217-333-7981; fax: +1-217-333-0508 (Y.S.J.).
    Search for more papers by this author
  • Hyunjoon Kong

    Corresponding author
    1. Department of Chemical and Biomolecular Engineering, University of Illinois, Urbana, Illinois; telephone: +1-217-333-1178; fax: +1-217-333-5052 (H.K.)
    • Department of Chemical and Biomolecular Engineering, University of Illinois, Urbana, Illinois; telephone: +1-217-333-1178; fax: +1-217-333-5052 (H.K.).
    Search for more papers by this author

Abstract

Microorganisms have become key components in many biotechnological processes to produce various chemicals and biofuels. The encapsulation of microbial cells in calcium cross-linked alginate gel beads has been extensively studied due to several advantages over using free cells. However, industrial use of alginate gel beads has been hampered by the low structural stability of the beads. In this study, we demonstrate that the incorporation of interpenetrating covalent cross-links in an ionically cross-linked alginate gel bead significantly enhances the bead's structural durability. The interpenetrating network (IPN) was prepared by first cross-linking alginate chemically modified with methacrylic groups, termed methacrylic alginate (MA), with calcium ions and subsequently conducting a photo cross-linking reaction. The resulting methacrylic alginate gel beads (IPN-MA) exhibited higher stiffness, ultimate strength and ultimate strain and also remained more stable in media either subjected to high shear or supplemented with chelating agents than calcium cross-linked alginate gel beads. Furthermore, yeast cells encapsulated in IPN-MA gel beads remained more metabolically active in ethanol production than those in calcium cross-linked alginate gel beads. Overall, the results of this study will be highly useful in designing encapsulation devices with improved structural durability for a broad array of prokaryotic and eukaryotic cells used in biochemical and industrial processes. Biotechnol. Bioeng. 2012;109: 63–73. © 2011 Wiley Periodicals, Inc.

Ancillary