The Importance of Extraction Protocol on the Analysis of Novel Waste Sources of Lignocellulosic Biomass

As the utilization and consumption of lignocellulosic biomass increases, so too will the need for an adequate supply of feedstock. To meet these needs, novel waste feedstock materials will need to be utilized. Exploitation of these novel feedstocks will require information both on the effects of solvent extraction on the succeeding analysis of potential novel feedstocks and how accurate current methodologies are in determining the composition of novel lignocellulosic feedstocks, particularly the carbohydrate and lignin fractions. In this study, the effects of solvent extraction on novel feedstocks, including tree foliage, tree bark and spent mushroom compost, with 95% ethanol, water and both sequentially were examined. Chemical analyses were carried out to determine the moisture content, ash, extractives, post-hydrolysis sugars, Klason lignin (KL) and acid-soluble lignin (ASL) within the selected feedstocks. The result of extraction could be seen most strongly for Klason lignin, with a strong association between higher levels of Klason lignin levels and greater amounts of non-removed extractives (tree foliage and bark). Higher Klason lignin levels are reported to be due the condensation of non-removed extractives during hydrolysis, hence the lower Klason lignin determinations following extraction are more exact. In addition, total sugar determinations were lower following extractions. This is because of the solubility of non-cell-wall carbohydrates; thus, the determinations following extraction are more accurate representations of structural cell-wall polysaccharides such as cellulose. Such determinations will assist in determining the best way to utilize novel feedstocks such as those analyzed in this work.