The Department of Energy recently awarded more than $1 million to a research project, “Imaging Lignin Degradation,” for a three-year period to a research team including George Kabalka, PhD, Professor, Robert H. Cole Neuroscience Endowed Chair and Director of Research, Radiology at the University of Tennessee Graduate School of Medicine, and investigators at Pennsylvania State University and Wesleyan University. Their research aims to identify novel enzymes that can be used to convert lignocellulosic material, found in wood, into bioethanol as an energy resource. The project will involve radioligand development and PET imaging, Dr. Kabalka’s area of expertise.
Lignocellulosic material is the most abundant renewable carbon source in the biosphere, however, it is encased in a lignin barrier and the barrier’s chemical recalcitrance is a major obstacle in the efficient utilization of lignocellulosic material. Lignin peroxidase, a lignin-degrading enzyme, was discovered 25 years ago but has proven to be one of the most expensive parts of converting lignocellulosic material to bioethanol. Since that time, the known list of enzymes capable of degrading lignin has not significantly increased, and this research team hopes to identify previously uncharacterized enzymes in the degradation and further utilization of lignin. The team has noted that lignin degradation occurs in complex environmental niches that are yet to be characterized, including within wood-feeding insects and in marine environments, and they hypothesize these niches contain microbial consortia that are distinct from the pure-culture systems where the peroxidases were discovered.
The research team plans to use near infrared fluorescence imaging to detect the initial biological depolymerization reactions of lignin. They then will use positron emission tomography to detect the initial biological depolymerization reactions of lignin and the subsequent degradation of the aromatic monomeric units. Using these methods, the researchers can potentially establish the presence and location of lignin degradation in previously unexplored ecological niches, providing the foundation for discovery of uncharacterized enzymes involved in lignin degradation and ultimately leading to improvements in lignocellulosic biomass utilization.
The primary investigator in this project is Ming Tien, PhD, Department of Biochemistry and Molecular Biology, Pennsylvania State University, with Dr. Kabalka and Erika Taylor, PhD, Department of Chemistry, Wesleyan University, participating as co-investigators.