EECE Seminar - Dr. Joshua Vermaas

Feb 14
11:00 AM
12:00 PM
Brauer Hall, room 12

Dr. Joshua Vermaas, Computational Scientist
Oak Ridge National Laboratory

Exploring biological mechanisms and materials to enable the bioeconomy through computational physics

ABSTRACT: Advances in physics tools and techniques have been fundamental in the study of biological processes at diverse length and timescales, with molecular simulation in particular probing length and timescales that would otherwise be inaccessible. This computational microscope can be applied to topics surrounding sustaina-bility, applying simulation tools to better un-derstand biological material properties at the nanoscale in the service of integrating biopoly-mers into industry. This includes lignin, an aro-matic heteropolymer found in the secondary cell walls of terrestrial plants. Due to its abun-dance, lignin is being evaluated as a feedstock for many bioproducts, but its utilization has been hampered by its heterogeneity at the molecular level. Recent progress in molecular simulation tools have enabled lignin simula-tion, elucidating critical parameters for under-standing lignin dynamics and structure within relevant molecular environments. These simu-lations quantify lignin nanostructure and poly-
mer expansion within specific solvent environ-ments, its affinity to cellulose, and its permea-bility across biological membranes. In each case, the results provide actionable intelligence to improve lignin utilization within the emerging bioeconomy. Solvent with modest polarity are shown to be optimal solvents for lignin. The swelling induced by these solvents reduces the contact surface with other biopolymers, reduc-ing their affinity and likely improving the separa-tions performance. The observed high permea-bility for small uncharged lignin compounds indicates that passive diffusion is likely enough for microbes to uptake lignin fragments, obvi-ating the need to engineer specific transport proteins for lignin. These results pave the way for future work in developing new materials from lignin.