Optimization of microwave-assisted calcium chloride pretreatment of corn stover.

National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beiertiao 1, Zhongguancun, Beijing 100190, PR China.

Bioresource technology 2013 Jan

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A 62.5% (w/w) CaCl(2) solution was used in the microwave pretreatment of corn stover. The central composite design (CCD) of response surface methodology (RSM) was employed to design and optimize the CaCl(2)-assisted microwave pretreatment (CaCl(2)-pretreatment). Temperature and time were the main factors affecting the enzymatic digestibility of corn stover. After CaCl(2)-pretreatment, hemicellulose degradation reached 85.90%, the specific surface area (SSA) increased by 168.93%, cellulose crystallinity index (CrI) decreased by 13.91% compared to untreated corn stover. The optimal conditions for glucose production with the CaCl(2)-pretreatment obtained by CCD were, 162.1 °C, 12 min and solid-to-liquid ratio 10% (w/v). Under these conditions, the enzymatic hydrolysis ratio of cellulose was 90.66% and glucose recovery was 65.47%. This novel process achieved the temperature of about 160 °C necessary for lignocellulose pretreatment under atmospheric pressure using the cheap calcium chloride as the heating medium. Copyright © 2012 Elsevier Ltd. All rights reserved.