Impact of harvest time and switchgrass cultivar on conversion to sugars and pyrolysis oils using biochemical and thermochemical routes

Authors: Serapiglia, Michelle; Mullen, Charles; Boateng, Akwasi; Dien, Bruce; Casler, Michael

Submitted to: American Chemical Society National Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 5/11/2016
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Switchgrass (Panicum virgatum L.), a perennial grass native to much of North America, is undergoing development as a dedicated energy crop. While high-biomass yield is necessary for the development of switchgrass as a bioenergy crop, composition of the biomass and nutrient content as they relate to biofuel conversion efficiency are also critical for sustainable energy production. Both biomass yield and composition can vary among cultivars depending on environmental conditions and harvest time for the crop. In order to evaluate the effects of harvest time on biomass composition, nutrient content, and biofuel yields of switchgrass cultivars, replicated trials across three sites (Arlington, WI, Marshfield, WI, and Urbana, IL) were established in 2009. The switchgrass cultivars were harvested once annually at upland peak, after killing frost, or post-winter in the spring for each growing season. Samples were processed using the biochemical or thermochemical routes for conversion to sugars and bio-oils, respectively. Near-infrared reflectance spectroscopy models were developed and utilized to characterize biomass traits and conversion potential among the cultivars. Mineral content was found to be highest in the biomass harvested at upland peak and decreased as harvest was delayed. Relative cell wall polymer content (i.e., hemicellulose, cellulose, and lignin) increased for the biomass as harvest was delayed. Changes in biomass yield and composition and their impacts on enzymatic sugar and potential ethanol yields and fast pyrolysis product yield will be presented and discussed.