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Chemical Engineering Research Seminar

Tina Jeoh

Department of Biological and Agricultural Engineering, University of California Davis

Abstract

Cellulose is a remarkable natural resource because of its vast abundance, its potential as a source of renewable glucose and its superior mechanical properties. A global pursuit of "advanced biofuels," envisioning the conversion of cellulose in agricultural plant residues (lignocellulosic biomass) to renewable fuels, has been on-going for seven decades but has faced significant technoeconomic barriers. Cellulose, a homopolymer of glucose subunits, is compositionally simple but structurally complex due to its organization into highly organized, crystalline fibrils. Chemical and biochemical reactions with cellulose is limited to interfacial interactions. Our work at UC Davis pursues the understanding of cellulose properties limiting enzymatic interactions with cellulose. Cellulase enzymes targeting the glycosidic bonds of cellulose are limited by the availability and accessibility to "productive binding sites" where enzymes can form active complexes. Enzymatic and chemical hydrolysis of cellulose depletes productive binding sites on the surface of cellulose. We have shown that the productive cellulase binding sites are the true substrates of cellulase enzymes, and that depletion of these sites (i.e. substrate depletion) stalls the reaction even when excess cellulose remains. Understanding structural and surface properties of cellulose limiting enzyme interaction kinetics will facilitate the engineering cost effective cellulose bioconversion processes.

Bio

Tina Jeoh is a Professor in the Biological and Agricultural Engineering Department at the University of California Davis. She earned her BS and MS in Biological Systems Engineering at Virginia Tech, her PhD in Biological and Environmental Engineering from Cornell University, and conducted her Post-Doctoral training at the National Renewable Energy Laboratory in Golden, Colorado. Prof. Jeoh’s research contributes to the vision of replacing petroleum-based products with sustainable sources; studying the breakdown of agricultural plant residues to release structural sugars for biological conversion to fuels, chemicals and materials. Prof. Jeoh’s group also develops sustainable, industrially-scalable microencapsulation technologies to improve storage stability and controlled delivery of bioactives for food, feed, agriculture, pharmaceutical, home care, personal care, and many other industries. Prof. Jeoh is passionate about empowering her students to engage in life-long learning, and she strives for gender equity in Science Technology Engineering and Mathematics (STEM). In partnership with the UC Davis Women’s Resources and Research Center (WRRC), she established the annual STEM for Girls outreach program that immerses underserved 5th-6th grade girls from surrounding communities in a day of STEM experiences while connecting with UC Davis STEM students, faculty and staff.