Cellulosic Ethanol: A Simulation Model of Lignocellulosic Biomass Deconstruction
Code: GROMACS
Allocation: 25.5 million hours
Cellulose—the stuff of switchgrass and hybrid poplar trees—has a bright future as ethanol, a relatively clean, renewable fuel for vehicles from lawn mowers to semi-trucks. The challenge is that cellulose lays hard to get and refuses to easily be hydrolyzed , meaning to react with water to form the glucose that ferments into ethanol. Because cellulose is just one part of the lignocellulose that forms plant cell walls, it is surrounded by other materials that complicate hydrolysis and cause unwanted byproducts in the reaction. Current pretreatments designed to improve the process—from changing pH and temperature to grinding and chipping the biomass—are expensive, energy intensive, and ultimately of limited success. Now a team led by Jeremy Smith of the University of Tennessee will use Oak Ridge National Laboratory’s petascale Jaguar supercomputer to conduct the most detailed simulation ever of the complex lignocellulosic biomass system, revealing the fate of cellulose at the molecular level during pretreatment. The researchers will focus on the structure, dynamics, and mechanics of cellulose in both crystalline and amorphous form, specifically noting how these forms change with temperature. Knowing this fundamental information, researchers can rework the pretreatment process to be more efficient and practical. Their work promises to help in the development of more cost-effective conversion of biomass to ethanol and another step toward an alternative to fossil fuels.
