A research aimed to lower the cost of biomass conversion process has been conducted by the researchers from the DOE’s Oak Ridge National Laboratory and Georgia Tech. The study used small-angle neutron scattering to test the structural impact of an acid pretreatment of lignocellulose from switchgrass.
To extract cellulose, switchgrass has to be pretreated and then through a series of enzymatic processes can be converted into sugars and then ethanol. The research could help the scientists identify the best pretreatment technology and lower the cost of making ethanol.
“My hope is that this paper and subsequent discussions about our observations will lead to a better understanding of the complex mechanisms of lignocellulose breakdown,” said co-author Volker Urban of ORNL’s Chemical Sciences Division.
A key finding is that native switchgrass that has been pretreated with hot dilute sulfuric acid undergoes significant morphological changes. While the data demonstrate that the switchgrass materials are very similar at length scales greater than 1,000 angstroms, the materials are profoundly different at shorter lengths. An angstrom is equal to 1/10th of a nanometer.
Urban and colleagues increased the crystalline portion of a cellulose fibril from 21 angstroms to 42 angstroms after treatment and found out that lignin undergoes a redistribution process and forms droplets at the same time. The droplets have 300 to 400 angstroms in size.
“Ultimately, the ability to extract meaningful structural information from different native and pretreated biomass samples will enable evaluation of various pretreatment protocols for cost-effective biofuels production,” he said.