美国普渡大学一项新的研究显示，植物细胞中的微孔可能是绿色燃料的希望。研究人员发现玉米秆颗粒在被用于生产乙醇时，发生了之前未知的结构变化。研究人员指出，他们的发现将有助于开发出利用植物进行大规模乙醇生产的一种可行方法。
他们的研究证实，预先用热水处理谷物植株组织，能够通过暴露植物细胞壁的微孔来增加反应的接触表面积，从而有助于细胞壁的降解。
普渡大学的研究人员指出，这种方法将加工技术与植物生理学联系在了一起。这项研究的结果发表在4月26日的Biotechnology and Bioengineering杂志上。
利用高分辨率的成像和化学分析方法，研究人员证实，这种预处理扩展了玉米秆细胞中的反应面积。在接下来的处理步骤中，这些张大的孔更容易被将纤维素转化成葡萄糖的酶攻击。产生的葡萄糖被发酵成乙醇。
论文的作者还指出，利用纤维素产生乙醇要比现有的几种工业加工方法更具优势。目前，几乎所有的工业乙醇都是由谷物或甘蔗中的淀粉加工而成。这种浪费大量粮食资源的方法使乙醇的产量很有限。而秸秆纤维素乙醇则有助于突破这个局限性。
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
Magnified image of cornstalk particle
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.
Received: 11 July 2006; Accepted: 30 November 2006
