Comparative data on effects of leading pretreatments and enzyme loadings and formulations on sugar yields from different switchgrass sources

Charles E. Wyman, Venkatesh Balan, Bruce E. Dale, Richard T. Elander, Matthew Falls, Bonnie Hames, Mark T. Holtzapple, Michael R. Ladisch, Y. Y. Lee, Nathan Mosier, Venkata R. Pallapolu, Jian Shi, Steven R. Thomas, Ryan E. Warner

Research output: Contribution to journalArticlepeer-review

114 Scopus citations


Dilute sulfuric acid (DA), sulfur dioxide (SO 2), liquid hot water (LHW), soaking in aqueous ammonia (SAA), ammonia fiber expansion (AFEX), and lime pretreatments were applied to Alamo, Dacotah, and Shawnee switchgrass. Application of the same analytical methods and material balance approaches facilitated meaningful comparisons of glucose and xylose yields from combined pretreatment and enzymatic hydrolysis. Use of a common supply of cellulase, beta-glucosidase, and xylanase also eased comparisons. All pretreatments enhanced sugar recovery from pretreatment and subsequent enzymatic hydrolysis substantially compared to untreated switchgrass. Adding beta-glucosidase was effective early in enzymatic hydrolysis while cellobiose levels were high but had limited effect on longer term yields at the enzyme loadings applied. Adding xylanase improved yields most for higher pH pretreatments where more xylan was left in the solids. Harvest time had more impact on performance than switchgrass variety, and microscopy showed changes in different features could impact performance by different pretreatments.

Original languageEnglish
Pages (from-to)11052-11062
Number of pages11
JournalBioresource Technology
Issue number24
StatePublished - Dec 2011

Bibliographical note

Funding Information:
Funding by the Office of the Biomass Program of the United States Department of Energy through Contract No. DE-FG36-07GO17102 to the University of California at Riverside was vital to performing this research. The true collaborative spirit of the CAFI Team made this project possible and pleasurable, and we thank the many undergraduate and graduate students, post-doctoral candidates, technicians, administrative assistants, and others on the CAFI Team for their vital role in developing this information. Dr. Rajeev Kumar from the University of California at Riverside provided very thorough and thoughtful reviews of the paper and offered many suggestions and corrections that are greatly appreciated. We also acknowledge that this paper records the final project by the CAFI team that has been together for over 10 years. Finally, the corresponding author would like to thank the Ford Motor Company for funding the Chair in Environmental Engineering that helps make projects such as this possible.


  • Hydrolysis
  • Microscopy
  • Pretreatment
  • Switchgrass
  • Yields

ASJC Scopus subject areas

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


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