Exit Seminar: Logan Robeck

Engineering a microbial cell factory for the valorization of lignin-derived aromatic compounds

Lignin is a biopolymer that comprises up to 30% of the biomass of woody plants, making it one of the most abundant sources of carbon on the planet. However, lignin’s heterogeneity and recalcitrance present barriers to its utilization. Chemo-biological processes using biocatalysts engineered from organisms such as Rhodococcus aromaticivorans RHA1 (RHA1), can circumvent these obstacles. In this work we used recently established genetic tools to improve RHA1’s biocatalytic potential. We developed a strain of RHA1 that can utilize all of the major aromatic components of depolymerized lignin at concentrations up to 15-fold higher than are tolerated by wildtype. We also developed gain of function mutants of LigV, a key aromatic-transforming enzyme, with increased activity on desired substrates. Finally, we introduced a wax-ester production cassette to increase this strain’s accumulation of lipids. This work moves us closer to developing biocatalysts to valorize an underutilized resource.