Acta Chimica Sinica ›› 2012, Vol. 70 ›› Issue (18): 1950-1956.DOI: 10.6023/A12050221 Previous Articles     Next Articles



刘建飞a,b, 曹妍a, 杨茂华a, 李会泉a, 邢建民a   

  1. a 中国科学院过程工程研究所 北京 100190;
    b 中国科学院研究生院 北京 100049
  • 投稿日期:2012-05-21 发布日期:2012-08-21
  • 通讯作者: 邢建民
  • 基金资助:

    项目受国家重点基础研究发展计划(973 计划)(No. 2009CB219901)、国家高技术研究发展计划(863 计划)(No. 2011AA02A203)、国家自然科学基金(No.21006118)和中国科学院知识创新工程重要方向项目(No. KSCX2-EW-G-2)资助.

Saccharification of the Pretreated Corn Stover by Microwave Assisted DMSO/AmimCl Co-solvents

Liu Jianfeia,b, Cao Yanaa, Yang Maohuaa, Li Huiquana, Xing Jianmina   

  1. a Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190;
    b Graduate University of Chinese Academy of Sciences, Beijing 100049
  • Received:2012-05-21 Published:2012-08-21
  • Supported by:

    Project supported by the National Basic Research Program of China (No. 2009CB219901), the National High Technology Research and Development Program of China (No. 2011AA02A203), the National Natural Science Foundation of China (No. 21006118) and the Knowledge Innovation Program of the Chinese Academy of Sciences (No. KSCX2-EW-G-2).

In order to enhance the enzymatic saccharification efficiency of corn stover, microwave assisted treatment with dimethyl sulfoxide (DMSO) and 1-ally-3-methylimidazolium (AmimCl) co-solvents was designed to break up the complicated chemical structure of corn stover. The pretreatment conditions were studied to increase the dissolution ratio, extraction ratio and cellulose I crystallinity index (CrI) variation. With the increase of AmimCl concentration, time and temperature of the pretreatment, the dissolution ratio, extraction ratio increased and CrI decreased. Considering the costs of high AmimCl concentration, degradation of biomass at high temperature and long time, the optimum conditions were DMSO/AmimCl co-solvents with a DMSO concentration of 15% (w) and 4 g corn stover per 100 g co-solvents. The optimum temperature and time were 110℃ and 60 min, respectively. Under the optimal conditions, the ratios of corn stover dissolution and extraction were as high as 46.6% and 22.9%, respectively. The cellulose saccharification ratio had a great increase within 14 h of enzymatic hydrolysis with an enzyme loading amount of 14 FPU/g solids. The saccharification ratio for the extracts was 71.4% in 14 h, while the ratio was only 12.5% for the raw corn stover in 20 h. Powder X-ray diffraction was used to determine the cellulose crystal structure. The cellulose I crystallinity index of corn stover residues decreased obviously and the crystal form of AmimCl extracts were transformed from Ⅰ to Ⅱ. From the SEM pictures of the materials, it could be seen that the outer surface of corn stover residues became rough, which was good for enzyme accessibility and saccharification. The AmimCl extracts had lost their natural status completely. By simple vacuum distillation, AmimCl could be recycled and its solubility kept almost constant. According to 1H NMR spectroscopy analysis, the structures of fresh and recycled AmimCl were almost the same. From the results mentioned above, it can be concluded that microwave assisted treatment with DMSO AmimCl co-solvents was a feasible method for corn stover pretreatment.

Key words: ionic liquid, corn stover, pretreatment, crystallinity, enzymatic saccharification