4. Conclusion
Hot water or dilute acid pretreatment with disk milling had
synergistic effects in increasing sugar yields. Sample with hot
water and milling improved glucose yields by 89% and xylose
yields by 134%. Particle size reduction after milling was not a primary
factor affecting enzymatic digestibility; rather, inhibitors
(acetic acid, furfural, HMF and formic acid) produced during pretreatment
primarily affected sugar yields. Hot water pretreated
milled samples and mild dilute acid pretreated milled samples
achieved comparable glucose yields, which were lower than harsh
dilute acid pretreated milled samples. Both combined processes
showed promise toward ethanol production by increasing enzyme
digestibility.