Pathways for biological conversion of lignin to lipids- a case study on Rhodococcus strains

A series of natural and engineered Rhodococcus strains (e.g. R. opacus PD630, R. opacus DSM 1069, R. jostii RHA1, and R. jostii RHA1 VanV^-) with lignin degradation and/or lipid biosynthesis capacities were selected to establish a fundamental understanding of the pathways and functional modules necessary to enable a platform for biological conversion of lignin to lipids. Profiles of metabolites produced by the Rhodococcus strains following growth on different carbon sources (e.g. alkali lignin, Kraft lignin, 4-hydroxybenzoic acid, and vanillic acid) suggested novel metabolic capacities in these organisms. The key challenge is to apply lignin degradation microorganisms that depolymerize lignin to reactive intermediates for oleaginous bacteria to produce lipids. The results lead to support for our hypothesis: Synthetic reconstruction and balanced modification of key regulators and enzymes in lignin depolymerization, aromatic compound catabolism, lipid biosynthesis, and other relevant processes, will enable Rhodococcus strains to efficiently convert lignin to lipid.