Abstract
Corn stover is one of the primary agricultural residues available for bioenergy production, but its cellular and tissue level complexity make it challenging to reduce to monomers that can then be converted to fuel and chemical precursors. The goal of this research is to improve the performance of corn stover for biochemical conversion to fuels and chemicals by reducing recalcitrance to deconstruction. The overarching aim of this research is to overcome the physiochemical barriers in corn stover that necessitate increased severity in conversion in terms of chemical loading, temperature, and time, during the residence time of long- and short-term storage operations. The hypothesis of this research is that low severity chemical and microbial treatment during long-term storage will reduce the degree of polymerization through saponification of ester-linked side chains or glycosidic bonds in hemicellulose or through oxidation of phenolic or non-phenolic components of lignin. These treatments will increase extractable components of corn stover, facilitate increased chemical impregnation, porosity, and solubilization of structural components, and lead to increased reactivity during downstream pretreatment. This novel approach focuses on moving recalcitrance reduction upstream in the feedstock supply chain, thus this passive operation that only preserves biomass will become an active environment that can positively impact conversion performance. Biological and chemical treatments applied during storage, one of the key unit operations in the feedstock logistics supply chain, were explored in this study with the goal of integrating these treatments into bioenergy logistics and conversion systems. Meanwhile, the mechanistic understanding of the biological and chemical reactions that can reduce biomass recalcitrance was obtained. The fundamental understanding on how these reactions change the biomass structure provided the scientific community with insight that can lead to new areas of exploration in bioenergy conversion.