Statistical modelling and optimization of alkaline peroxide
oxidation pretreatment process on rice husk cellulosic
biomass to enhance enzymatic convertibility
and fermentation to ethanol
The complex and ordered arrangements of
the lignocellulosic materials make them recalcitrant
for their conversions to ethanol. Pretreatment is a
crucial step in overcoming these hindrances. In this
study, a 23
-full factorial design of experiments optimization technique was applied on the alkaline
peroxide oxidation pretreatments of rice husks biomass. The low–high levels of the influencing variables
on pretreatments were; temperature (100–120 C),
time (1–2 h), % (v/v)H2O2 concentration (1–3%).
Under the prevailing pretreatments, the optimum
conditions were predicted and validated to be
109 C, 2 h, and 1.38% H2O2 which yielded
56% (w/w) cellulose content, 55% (w/w) hemicellulose solubilization, and 48% (w/w) lignin removal. At
the established optimum pretreatment conditions, and
considering variations in biomass and enzymes loadings, maximum reducing sugars production was
205 mg/g dry biomass at different enzymatic hydrolysis conditions of 3% biomass loading, hydrolysis temperature of 45 C, hydrolysis time of 24 h,
and 35 FPU/g cellulose enzyme loading. The highest
cellulose conversion of 33% yielded 24 g/L ethanol at
the end of the first day of saccharification and
fermentation. Physical, structural, and morphological
investigations on raw and treated materials using tools
such as stereomicroscopy, scanning electron microscopy, and fourier transform infrared spectroscopy
further revealed the effectiveness of chosen method on
rice husks biomas