(193b) Combined Alkali Treatment and Anaerobic Storage in Corn Stover Enhances Reactivity and Surface Energy Properties

The inherent recalcitrance of lignocellulosic biomass to physical and chemical depolymerization necessitates high severity thermal and chemical treatments to liberate carbohydrates and lignin for production of fuels and chemicals. The aim of this study was to examine the potential for process intensification within the feedstock supply chain operation of long-term storage. The aim was to use anaerobic storage to provide an environment conducive to slow transformations in corn stover following saponification of ester bonds in lignin and hemicellulose brought about by alkali addition. Results indicate the alkali-treated corn stover was well preserved in anaerobic storage over 2 weeks, showing only 4% dry matter loss. Monomerization of glucose and xylose in the presence of glycosidases confirmed the alkali-treated, stored biomass was more susceptible to enzymatic cleavage, suggesting reduced recalcitrance. Washing at room temperature was employed to remove any molecules that could be blocking enzyme assess. Washing increased enzymatic accessibility in terms of carbohydrate monomerization in the native sample and increased surface area in both native and alkali-stored samples. Surface energy confirmed the unwashed samples contained equivalent basic features, which primarily are attributed to lignin, yet washing removed the coalesced lignin in the alkali-treated stored samples. The alkali-stored, washed stover exhibited increased surface area, hydrophilicity, and work of cohesion and adhesion compared to the native, washed samples. This research drives the fundamental understanding that adding alkali prior to anaerobic storage not only improves enzyme accessibility to corn stover but, when combined with a room temperature wash, will result in a product that has favorable physical properties in downstream preprocessing.