The culture of Scenedesmus dimorphus at the laboratory scale has often been in standard microalgae media, such as 3N-Basal Bold medium (3N-BB), which contains 15 different chemicals. Given the extremely tight profit margins of large-scale production of biofuel from microalgae, it is important to identify the minimally sufficient quantities of nutrients necessary to maximize lipid productivity. The individual and interactive effects of six groupings of the components of 3N-BB medium on growth rate, lipid content, and total biomass yield of S. dimorphus were determined. Trace metal and vitamin concentrations were reduced to 1/6 the level of 3N-BB medium without adversely affecting growth rates and biomass concentration, while concentrations of CaCl2 and K2HPO4/KH2PO4 were reduced to 1/10 that of 3N-BB without adversely affecting biomass and lipid concentrations. Both lipid productivity and lipid content were maximized at the lowest NaNO3 concentration (1/10 that in 3N-BB) and independent of MgSO4 concentration, while the interaction of these two chemicals enhanced biomass concentration. (c) 2013 American Institute of Chemical Engineers Environ Prog, 32: 937-945, 2013