CELLULASE IMMOBILIZATIONS WITH HIGHLY RETAINED ENZYMATIC ACTIVITIES

• Author / Creator

  Ikeda, Yuko

• Immobilization has the potential to make enzyme utilization more cost efficient, but reduced enzymatic activity makes it unfeasible. The purpose of this study was to develop immobilized cellulase systems on silica supports that retain high enzymatic activity. Two of the four systems created resulted in better-than-expected productivity during hydrolysis and make good candidates for further research.
  The immobilized systems on fumed non-porous silica retained enzyme activity equivalent to free cellulases when hydrolyzing crystalline cellulose. However, sugar composition analysis indicated that immobilization decreased cellobiose conversion to glucose, resulting in substantial cellobiose production. More research is required to understand the mechanism at work. The immobilized cellulases obtained wider pH stability, but displayed decreased thermal and ionic stability. Storage stability was unchanged. One major finding was increased enzyme reusability, with activity remaining at 30% after nine uses.
  When lignocellulose biomass was used for hydrolysis, production was substantially lower than when using free cellulases. It is hypothesized that the immobilized cellulases had difficulty hydrolyzing the amorphous regions of the lignocellulose. Although further optimization is necessary, the immobilized cellulase systems developed in this study contribute greatly to increasing the commercial viability of hydrolysis and lignocellulose pretreatment.

• Subjects / Keywords

  • Biorefinery
  • Cellulases
  • Immobilization

• Graduation date

  Fall 2013

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3W67N

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.