(357e) Effects of Biomass Ash and Ash-Forming Elements on Biomass Pretreatment and Enzymatic Hydrolysis

Biomass ash is usually considered to bring negative impacts on biomass pretreatment and enzymatic hydrolysis for sugar production for biofuel. Other than the obvious impact on the decrease proportion of carbohydrate constituents in biomass as the ash content increases, the fundamental impacts of biomass ash on the processing are still not fully understood. Ash from biomass combustion was used in different pretreatment methods and enzymatic hydrolysis to understand its impact on sugar yield including the performance of the process in terms of product inhibitors and removals of carbohydrates and lignin in this study. Several metal chlorides representing alkali and alkaline earth metals (AAEMs) and transition metals as parts of ash-forming elements were used in aqueous pretreatment of acid-washed corn stover to further study the impact of each metal ions on the sugar yield. This process was then followed by enzymatic hydrolysis and the sugar yield was determined. Physicochemical changes of the pretreated corn stover were also analyzed to confirm the result. Results showed negative effects of biomass ash on the yield of glucose and xylose after pretreatment but interestingly, glucose and xylose yield from enzymatic hydrolysis was not compromised. This study provided better understanding of effects of metal salts on the pretreatment and sequential biomass conversion process in order to develop novel, cost-effective, and efficient biomass pretreatment technology.