Effect of substrate on the lipids of the hydrocarbon-utilizing Mycobacterium vaccae

Cells of Mycobacterium vaccae strain JOB5 grown on ethane, propane, or n-butane contained about twice as much lipid as cells grown on acetate, isopropanol, or propionate. Propane-grown cells contained more neutral lipid (34.4%) than acetate-grown cells (19.4%) and there was a correspondingly greater percentage of phospholipid in acetate-grown cells. When cells grown on acetate were harvested and resuspended in a growth medium with propane as substrate, the synthesis of lipid preceded synthesis of nitrogenous components and cell multiplication. The lipid fraction that increased most by growth on propane was triglyceride. It is suggested that this lipid may play a role in the assimilation of the hydrophobic hydrocarbon substrate.