Effects of Different Stem Skin and Marrow Root Mesh Sizes in Sweet Sorghum Bagasse on the Release of Sugar in Hydrolysis

Abstract

This study investigates the effects of different particle sizes of sweet sorghum stem skin and marrow on pretreatment and hydrolysis. The optimal pretreatment concentration was 3.5% acid and 6.5% alkali. The optimal pretreatment temperature was 35 °C. Solid recovery gradually decreased with an increase in mesh and achieved 41.05% at 100 mesh under selected pretreatment conditions. The surface of the pretreated stem skin and marrow became rugged and pores were emerged. In addition, pore size was larger compared with untreated specimens. Pore diameter Dv (d) could reach 57.4 μm. For enzymatic hydrolysis, 20 units/g cellulase and 40 units/g β-glucosidase were adopted, and ten types of monosaccharide were obtained, including glucose, xylose, arabinose, galactose, mannose, ribose, fucose, gluconic acid, gluconic acid and rhamnose. The total monosaccharide content for stem skin and marrow were reached 1381.99 ± 0.7 mg/kg at 100 mesh with a two-stage (alkali–acid) pretreatment.