초록
<P><B>Abstract</B></P> <P>Giant reed (<I>Arundo donax</I> L.) is a perennial grass and a promising energy crop of high biomass yield and lower tillage requirement. The liquid ammonia pretreatment (LAT) conditions were optimized to maximize sugar release of giant reed using a response surface methodology (RSM) on Box-Behnken design by varying temperature, water loading, ammonia loading and residence time. The results showed that the ammonia loading and temperature had more significant effects than water loading and residence time on polysaccharide conversion. Enzymatic glucan and xylan digestibility of LAT-treated substrate after 72 h using cocktail enzymes including cellulase, β-glucosidase and xylanase were 94.2% and 84.4%, respectively. The scanning electron microscopy (SEM) images indicated that the porous biomass structure was formed due to cellulose swelling and lignin relocation by LAT process, resulting in improving the cellulose accessibility to enzymes, both factors contributing to improved enzymatic digestibility.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A modified AFEX method, named liquid ammonia pretreatment (LAT) was proposed. </LI> <LI> Pretreatment conditions of giant reed (<I>Arundo donax</I> L.) were optimized by RSM. </LI> <LI> Enzymatic glucan conversion and xylan conversion were 94.2% and 84.4%. </LI> <LI> SEM images showed that the porous biomass structure was formed by LAT process. </LI> <LI> LAT pretreatment was an effective pretreatment method for energy crops. </LI> </UL> </P>