A New Approach to Using Dried Hybrid Poplar as a Potential Commodity Feedstock for Sugar Production

Abstract

Use of a commodity feedstock with uniform physical and chemical characteristics can maximize the efficiency of sugar production in a lignocellulosic biorefinery. However, efficient handling and storage necessitates dry biomass, while effective bioconversion is maximized with high moisture biomass. To bridge this gap, the effect of moisture content on hybrid poplar bioconversion was investigated. Fresh hybrid poplar chips were both oven-and air-dried and rehydrated by soaking in water prior to SO 2 -catalyzed steam explosion. Following enzymatic hydrolysis, pretreated solids derived from air-dried and ovendried chips (10% and 0% moisture content) were 11−24% less digestible than never-dried chips at 50% moisture content. Upon soaking the same poplar chips in water prior to SO 2 impregnation, pretreatment, and hydrolysis, there was a dramatic improvement in digestibility of up to 44%, thought to be due to improved SO 2 uptake and subsequent hemicellulose hydrolysis in the dried chips. Monomeric glucose and xylose yields after pretreatment and hydrolysis of over 500 kg/tonne raw biomass were achieved from oven-dried and soaked biomass compared to only 349 kg/tonne raw biomass for unsoaked oven-dried biomass. In contrast, no improvement was observed upon soaking for air-dried or never-dried hybrid poplar chips.

Natural acetylation impacts carbohydrate recovery during deconstruction of Populus trichocarpa wood

“…Acetate endogenous to woody biomass could improve sugar release during pretreatment, an effect also noted by Ewanick et al [ 60 ]. Acetate hydrolysis did not vary with wood cellulose content, which is consistent with the hypothesis that interactions between acetate and the cellulose microfibril are minimal [ 61 ].…”