EFFECT OF COMBINATION OF LIQUID HOT WATER SYSTEM AND HYDROGEN PEROXIDE PRETREATMENT ON ENZYMATIC SACCHARIFICATION OF CORN COB

Abstract

Alkaline hydrogen peroxide pretreatment is an effectively enhance the increasing enzymatic
digestibility of lignocellulosic biomass for conversion to fuels and chemicals in the biorefinery processes. In
this study, effects of H2O2 on monomeric sugar in the liquid fraction during hydrogen peroxide pretreatment
and sugar after enzymatic hydrolysis from corncobs were studied under varying reaction conditions. The
temperature (30-120o
C) and H2O2 concentration (2.5-10%) efficiently promoted sugar yield in the piqued
fraction and improved enzymatic hydrolysis of pretreated solids. The optimal condition for H2O2 pretreatment
of corncob (H2O2 concentration of 5% using 60 o
C for 2 h) increased hemicellulose solubilization into the
aqueous phase, resulting into the maximized pentose yield of 61.88% (xylose + arabinose) in the aqueous phase.
H2O2 pretreatment under the optimal conditions at 60o
C for 2 h, leading to the enhance glucose yield from
enzymatic hydrolysis of the pretreated biomass using 10 FPU/g CelluclastTM (85.66 %) and small amount of
formation of inhibitory by-products. Combined with glucose in the aqueous phase, this resulted in the maxima
95.61% glucose recovery from the native corncob. This was related to changes in crystallinity and surface area
of the pretreated biomass. Scanning electron microscopy (SEM) showed disruption of the intact biomass
structure resulting increasing enzyme’s accessibility to the cellulose microfibers which showed higher
crystallinity index compared to the native biomass as shown by X-ray diffraction with a marked increase in
surface area as revealed by BET measurement. The results provided efficiency of H2O2 pretreatment on
increasing sugar recovery and an efficient approach for its processing in biorefinery industry.