Monday, April 29, 2013
Exhibit Hall
Recalcitrance of lignocellulose is a major barrier to the economical development of biobased fuels and products. To overcome the recalcitrance of lignocellulosic biomass, many chemical, thermal and biological pretreatments have been proposed. The effectiveness of the pretreatments has been mainly investigated based on the sugar yield after pretreatment and the hydrolysability of resulting substrates. There is insufficient understanding of the reaction chemistries occurred during pretreatment processes and the degradation pathways of the soluble compounds. This information is of a great importance to minimizing the adverse effects of inhibitory substances generated from pretreatment step and identifying new intermediate compounds for biofuel and chemicals production in subsequent process steps.
In this study, pretreatment of Douglas fir by alkaline peroxide was investigated and compared with diluted acid pretreatment with a focus on the carbohydrate and lignin degradation pathways. The effects of different pretreatment chemistries and severities on chemo-selectivity of the degradation products were determined. In contrast to diluted acid pretreatment, alkaline peroxide pretreatment of softwood led to a different sugar degradation pathway where lactic acid, glycolic acid and glyceraldehyde were produced as main products. The sugar and lignin degradation pathways during alkaline peroxide pretreatment were illustrated and the hydrolysability of pretreated substrates was determined.