(482b) Impacts of Cell Wall Hydrophilicity On the Enzymatic Deconstruction of Diverse Biomass Feedstocks and Pretreatments

This work will present research results relating the environment of the water in the cell wall to the potential for enzyme-catalyzed depolymerization of plant cell wall polysaccharides from diverse plant cell walls treated with a range of pretreatments.  These biomass feedstocks will include grasses using alkaline hydrogen peroxide (AHP) as a chemical pretreatment or as a post-treatment following liquid hot water pretreatment (LHW) as well as hardwoods delignified by either soda pulping or organosolv pulping.  The effect of pretreatment on the carbohydrate and lignin composition after pretreatment and fiber swelling behavior will be shown.  We hypothesize that the digestibility improvement resulting from may be attributed to mild oxidation or solubilization of the lignin remaining in the cell wall and, for grasses, destruction of ferulate crosslinks between cell wall polymers which would have the net effect of increasing the hydrophilicity to allow improved water and enzyme penetration into the cell wall.  To test this hypothesis, we will correlate the hydrophilicity of the cell wall as measured indirectly by lignin and cell wall carboxylic acid content and total lignin content to water swelling capacity and digestibility. Additionally the effects of shear-induced fibrillation and particle size reduction on water will be quantified as well.