Big bluestem as a bioenergy crop: A review

Big bluestem (Andropogon gerardii) is an ecologically dominant warm-season (C4) perennial native grass that comprises as much as 80% of the plant biomass in prairies in the grasslands of the North American Midwest. Ranchers adopted the species as a forage crop long ago, but its high cellulosic content and low agricultural input requirements recently have made big bluestem a promising feedstock for ethanol production and bio-oil. The objective of this paper is to review big bluestem׳s potential as a bioenergy crop with respect to both biology and conversion. Biology includes distribution and adaptation of big bluestem, ecotypes and varieties currently studied, production management, and disease and pest control. Conversion includes discussion of the conversion of big bluestem biomass to bio-ethanol and bio-oil. Estimated ethanol yield of big bluestem is about 1886 L/ha, which is comparable to previously reported herbaceous biomasses. Various constraints and potential applications of big bluestem as an energy crop are analyzed in the final section of this paper. Plant breeding research that focuses on modifying big bluestem composition to minimize recalcitrance to bioconversion and increasing biomass yields is imperative.