(a) A corn stover particle shows a smooth surface with a few micron-sized pores after enzyme hydrolysis converted 11% of cellulose to glucose in 3 h. (b) This corn stover particle has many more pores. It was pretreated in water at 190°C for 15 min and hydrolyzed by enzymes at 50°C for 3 h, resulting in 40% cellulose conversion to glucose. The results illustrate that pretreatment changes lignocellulosic-structure susceptibility to attack by enzymes. Higher resolution in future imaging techniques will facilitate a deeper understanding of underlying molecular mechanisms.
Credit or Source: Images and conditions from unpublished work of M. Zeng, N. Mosier, C. Huang, D. Sherman, and M. Ladisch, 2006.
U.S. DOE. 2006. Breaking the Biological Barriers to Cellulosic Ethanol: A Joint Research Agenda, DOE/SC/EE-0095, U.S. Department of Energy Office of Science and Office of Energy Efficiency and Renewable Energy. (p. 88) (website)