Abstract
Biomass ash was added during pretreatment and enzymatic hydrolysis to examine its influence on biochemical processes for producing fermentable sugars. Corn stover was pretreated using several methods - hot water, dilute acid, alkaline, γ-valerolactone, and ionic liquid methods, each examined with ash loadings of 8.26% and 13.21%. The findings demonstrated that increased ash content adversely affected both pretreatment and enzymatic hydrolysis. Specifically, the total sugar yield was 3–15% lower at the higher ash content across all pretreatment methods, and up to 6.7% lower during enzymatic hydrolysis. For acidic pretreatment, the sugar yield decreased as ash content increased. In contrast, ash content had a lesser impact on alkaline pretreatment compared to acidic pretreatment. The primary reasons for the reduced sugar yield in higher-ash biomass during acidic pretreatments were likely the neutralizing effect of the ash and decreased acid access to the substrates. During enzymatic hydrolysis, ash reduced the sugar yield by limiting enzyme access to cellulose.