普渡大学(Purdue University)的研究人员发现,将植物的秆,叶或纤维素以热水进行前处理,将有利于生质酒精的大量制造,相较于未处理的原料,其产率可提高3~4倍。研究人员发现在热水处理过的植物细胞壁中,有许多微小的孔洞产生,能增加纤维素分解酵素作用的表面积,更有效的将纤维素分解为小分子的葡萄糖,提供酵母菌制作酒精的原料。此研究发表于4月26日的Biotechnology and Bioengineering期刊。由Nathan Mosier教授主导研究进行。
研究人员利用高分辨率的影像及化学分析,来观察以热水前处理过的植物细胞壁,发现细胞壁上被扩大的孔洞能使酵素轻易的作用,提高纤维素被分解的速率,这也将改善美国生质酒精生产的限制,因为过去大多是利用玉米粒或甘蔗等作物作为制造生质酒精的原料,可能会影响经济作物的出口值,或影响动物饲料的来源,若能以其它植物性纤维素作为生质酒精的原料,将可破除这些限制,更有利于工业上大量生质酒精的制造。
(编译/陈瑞娟) (资料来源 : Bio.com)
原始出处:
Article
Microscopic examination of changes of plant cell structure in corn stover due to hot water pretreatment and enzymatic hydrolysis
Meijuan Zeng 1 2, Nathan S. Mosier 1 2, Chia-Ping Huang 4, Debra M. Sherman 4, Michael R. Ladisch 1 2 3 *
1Laboratory of Renewable Resources Engineering, Potter Engineering Center, 500 Central Drive, Purdue University, West Lafayette, Indiana 47907; telephone: 765-494-7022, fax: 765-494-7023
2Department of Agricultural and Biological Engineering, Purdue University, 225 South University Street, West Lafayette, Indiana 47907
3Weldon School of Biomedical Engineering, Purdue University, 206 S. Intramural Drive, West Lafayette, Indiana 47907
4Life Science Microscopy Facility, Purdue University, S-052 Whistler Building, 170 S. University Street, West Lafayette, Indiana 47907
email: Michael R. Ladisch (ladisch@purdue.edu)
*Correspondence to Michael R. Ladisch, Laboratory of Renewable Resources Engineering, Potter Engineering Center, 500 Central Drive, Purdue University, West Lafayette, Indiana 47907; telephone: 765-494-7022, fax: 765-494-7023.
Funded by:
U.S. Department of Agriculture
U.S. Department of Energy
Agricultural Research Programs at Purdue University
Purdue University; Grant Number: IFAFS 00-52104-9663, DE-FC36-01GO11075
Keywords
corn stover ?particle size ?hot water pretreatment ?enzymatic hydrolysis ?SEM image ?glucose conversion ?accessible surface area
Abstract
Particle size associated with accessible surface area has a significant impact on the saccharification of plant cell walls by cellulolytic enzymes. Small particle sizes of untreated cellulosic substrate are more readily hydrolyzed than large ones because of higher specific surface area. Pretreatment enlarges accessible and susceptible surface area leading to enhanced cellulose hydrolysis. These hypotheses were tested using ground corn stover in the size ranges of 425-710 and 53-75 祄. Ultrastructural changes in these particles were imaged after treatment with cellulolytic enzymes before and after liquid hot water pretreatment. The smaller 53-75 祄 corn stover particles are 1.5?more susceptible to hydrolysis than 425-710 祄 corn stover particles. This difference between the two particle size ranges is eliminated when the stover is pretreated with liquid hot water pretreatment at 190癈 for 15 min, at pH between 4.3 and 6.2. This pretreatment causes ultrastructural changes and formation of micron-sized pores that make the cellulose more accessible to hydrolytic enzymes. Biotechnol. Bioeng. 2007;97: 265-278. © 2006 Wiley Periodicals, Inc.