Impact of mixed feedstocks and feedstock densification on ionic liquid pretreatment efficiency

Background: Lignocellulosic biorefineries must be able to efficiently process the regional feedstocks that are available at cost-competitive prices year round. These feedstocks typically have low energy densities and vary significantly in composition. One potential solution to these issues is blending and/or densifying the feedstocks in order to create a uniform feedstock. Results & discussion: We have mixed four feedstocks – switchgrass, lodgepole pine, corn stover and eucalyptus – in flour and pellet form, and processed them using the ionic liquid 1-ethyl-3-methylimidazolium acetate. Sugar yields from both the mixed flour and pelletized feedstocks reach 90% within 24 h of saccharification. Conclusion: Mixed feedstocks, in either flour or pellet form, are efficiently processed using this pretreatment process, and demonstrate that this approach has significant potential.