Fig. 1

Conversion of phenol to lipids by R. opacus PD630. a Cell membrane structure and simplified model for conversion of a lignin monomer (phenol) to lipids by R. opacus PD630 [42]. Phenol is imported into the cell and converted to central metabolic intermediates acetyl-CoA and succinyl-CoA [20, 72]. Next, acetyl-CoA is converted into acyl-CoAs by fatty acid synthase (FAS) Ia [32]. Phospholipids (PLs), triacylglycerols (TAGs), and α-branches of mycolic acids (MAs) are synthesized using acyl-CoAs from FAS Ia, while meromycolate branches for mycolic acids are synthesized by further chain elongation using other fatty acid synthases (FAS II) or mycocerosic acid synthases (MAS) [32]. Triacylglycerols can be stored in lipid droplets [30]. PM phospholipid membrane, PG peptidoglycan layer, AG arabinogalactan layer, MM mycomembrane, and OL outer layer. b Representative structures of lipid types examined in this work.