11-15: Xylose and glucose yields from dilute acid pretreatment and enzymatic hydrolysis of mixed hardwood

The possibility to use mixed hardwood as a feedstock in a biochemical-based refinery represents a great advantage by reducing the biomass processing cost and providing more carbohydrate per exploited forest area. Most studies on the production of fermentable sugars from hardwood biomass are conducted using pure wood, free of any bark biomass or any other woody products. As a consequence, little information is available on how any biomass contamination could affect the sugar yields during the biochemical conversion of the biomass. This current work describes the effects of contaminating the sweetgum wood with sweetgum bark, oak bark, or oak wood on the recovery of xylose and glucose during dilute acid pretreatment and enzymatic hydrolysis. The hardwood biomass, consisting of 70% sweetgum wood and 30% contaminant (sweetgum bark, oak bark, or oak wood), was pretreated with 0.98% (v/v) sulfuric acid at 160¢ªC for 60 min. The resulting pretreated solid was hydrolyzed further with a cellulose enzyme cocktail in a shaking water bath at 55¢ªC and 100 rpm. Preliminary results show that the contamination with bark biomass prevents the degradation of xylose during pretreatment. Contamination with sweetgum bark or oak bark yielded the highest xylose recovery of 84% and 80%, respectively. On the other hand, both bark biomasses did not affect the glucose yield.  The contamination with oak wood yielded the highest glucose recovery of 87%.