Effects of enzyme loading and β-glucosidase supplementation on enzymatic hydrolysis of switchgrass processed by leading pretreatment technologies

Venkata Ramesh Pallapolu, Y. Y. Lee, Rebecca J. Garlock, Venkatesh Balan, Bruce E. Dale, Youngmi Kim, Nathan S. Mosier, Michael R. Ladisch, Matthew Falls, Mark T. Holtzapple, Rocio Sierra-Ramirez, Jian Shi, Mirvat A. Ebrik, Tim Redmond, Bin Yang, Charles E. Wyman, Bryon S. Donohoe, Todd B. Vinzant, Richard T. Elander, Bonnie HamesSteve Thomas, Ryan E. Warner

Research output: Contribution to journalArticlepeer-review

53 Scopus citations


The objective of this work is to investigate the effects of cellulase loading and β-glucosidase supplementation on enzymatic hydrolysis of pretreated Dacotah switchgrass. To assess the difference among various pretreatment methods, the profiles of sugars and intermediates were determined for differently treated substrates. For all pretreatments, 72h glucan/xylan digestibilities increased sharply with enzyme loading up to 25mg protein/g-glucan, after which the response varied depending on the pretreatment method. For a fixed level of enzyme loading, dilute sulfuric acid (DA), SO 2, and Lime pretreatments exhibited higher digestibility than the soaking in aqueous ammonia (SAA) and ammonia fiber expansion (AFEX). Supplementation of Novozyme-188 to Spezyme-CP improved the 72h glucan digestibility only for the SAA treated samples. The effect of β-glucosidase supplementation was discernible only at the early phase of hydrolysis where accumulation of cellobiose and oligomers is significant. Addition of β-glucosidase increased the xylan digestibility of alkaline treated samples due to the β-xylosidase activity present in Novozyme-188.

Original languageEnglish
Pages (from-to)11115-11120
Number of pages6
JournalBioresource Technology
Issue number24
StatePublished - Dec 2011

Bibliographical note

Funding Information:
We gratefully acknowledge the financial support provided by the Office of the Biomass Program of DOE (Contract: DE-FG36-07GO17102 ). We also wish to thank the members of CAFI team for their useful suggestions and collaboration, Genencor-Dansico (Paulo Alto, CA) for providing the enzymes used in this research and Ceres, Inc. (Thousand Oaks, CA) for providing switchgrass feedstocks.


  • Cellulase
  • Digestibility
  • Pretreatment
  • Switchgrass
  • β-Glucosidase

ASJC Scopus subject areas

  • Bioengineering
  • Environmental Engineering
  • Renewable Energy, Sustainability and the Environment
  • Waste Management and Disposal


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