Everything Biomass

BCRL Publications

Optimization of AFEX™ pretreatment conditions and enzyme mixtures to maximize sugar release from upland and lowland switchgrass


Switchgrass is a North American grass that is considered to be a highly promising herbaceous bioenergy
feedstock. Differences in processing conditions and yields specifically related to switchgrass cultivar or
cytotype (upland or lowland) can be confounded by differences in harvest date or region of growth.
For this research, AFEX™ pretreatment conditions and hydrolysis enzyme mixtures were statistically
optimized for Alamo (lowland) and Shawnee (upland) switchgrass that had been harvested in December
in Oklahoma. Optimal pretreatment conditions and enzyme mixtures were almost identical for both varieties
and gave similar mass sugar yields. Inclusion of hemicellulases in the enzyme mixture maintained
total sugar yields with 50% reduction in enzyme loading. Regardless of variety, the biorefinery should be
able to obtain high sugar yields using the same pretreatment and hydrolysis conditions to process
switchgrass grown under the same environmental conditions, in the same location, and harvested at
the same time of the year.

Download Article
Biomass Conversion Research Laboratory
Michigan State University
3815 Technology Blvd Lansing, MI 48910
517.432.0157 Fax 517.423.1105