Although a rigorous definition of growth-limiting substrate relies on a kinetic anal., a simple stoichiometric anal. based on the calcn. of the conversion is more applicable. Anal. of single and dual limitations is based on a simulated example for a substrate taken-up by facilitated diffusion (e.g. glucose) or by free diffusion (e.g. ethanol) and shows that a kinetic single or dual limitation can usually be predicted by comparing the conversion of two nutrients with the expected stoichiometry. Stoichiometric anal. of dual limitations is applied to exptl. data for Kluyveromyces marxianus (for glucose and oxygen) and Saccharomyces cerevisiae (for glucose and ammonium). [on SciFinder (R)]