Effects of dilute acid and flowthrough pretreatments and BSA supplementation on enzymatic deconstruction of poplar by cellulase and xylanase

Abstract

To help understand factors controlling the recalcitrance of lignocellulosic biomass to deconstruction to sugars, poplar was pretreated with liquid hot water (LHW) and extremely dilute acid (EDA) at 140°C and 180°C in batch and flowthrough reactors. The resulting solids were then subjected to enzymatic hydrolysis by eight combinations of cellulase, xylanase, and bovine serum albumin (BSA). Co-addition of xylanase to cellulase resulted in up to 11 percentage points higher overall sugar yield than their sequential addition. In general, supplementation of BSA to enzymes had a larger impact on flowthrough solids with reduced lignin content than batch solids with high lignin content. BSA did not affect xylan yields and while it had low impact on LHW solids, it caused large increases in sugar yields from EDA solids. Flowthrough pretreatment produced less recalcitrant solids than did batch operation, but using very dilute acid reduced recalcitrance even more.