(347b) Exploring Antimicrobial Properties of Lignin Derived Compounds and Materials

This study examines the antimicrobial properties of lignin containing hydrogel materials and thermochemically processed lignin-rich waste streams. We first explored the use of ionic liquids as solvents for creating hydrogels from mixtures of cellulose, xylan, Kraft lignin, in addition to both poplar wood and biomass sorghum to examine their effects on gel formation and antimicrobial properties against Escherichia coli. The chemical and physical properties of generated hydrogels were characterized using FT-IR, SEM, XRD, swelling kinetics, and stress-strain analysis. Additionally, two lignin rich streams, residues from the enzymatic hydrolysis of dilute acid and alkaline pretreated corn stover, were decomposed via pyrolysis and catalytic transfer hydrogenolysis, respectively. The resulting liquid bio-oils were subjected to sequential organic solvent extractions and characterized through HPLC and GC/MS. These extracted compounds were screened against Saccharomyces cerevisiae (yeast), Escherichia coli, and Lactobacillus amylovorus for antimicrobial properties. Six lignin model monomers: guaiacol, vanillin, vanillic acid, syringaldehyde, 2,6-dimethoxyphenol, and syringic acid were compared to the oils and extracted fractions to compare antimicrobial properties. This study provides insight into using ionic liquids for gel formation from lignocellulosic components and the antimicrobial potential of lignin derived compounds.