To verify which pretreatment was the most effective in terms of
enzyme accessibility to the substrate, hydrolysis was conducted
using bagasse with and without alkali pretreatment. After 24 h of
hydrolysis at 42 C using only acid-pretreated bagasse, 8.9 g/L of
glucose were released while 18.36 g/L of glucose were released
when the acid–alkali pretreatment was used. The average glucose
yields for the two treatments differed significantly according to
ANOVA (p-value = 0.005). Twofold more glucose was released after
hydrolysis with the acid–alkali pretreatment than the acid pretreatment.
With the removal of lignin and hemicellulose by the
acid–alkali pretreatment, cellulose became more accessible to the
enzymes in the hydrolysis step. According to Santos et al. (2010),
the presence of lignin limits the process of enzyme diffusion in
the substrate and consequently the release of glucose.