Utilizing a pulsed-laser fluorescent detection system to enable the simultaneous measurement of the native 20 L-aminopeptidases (APs) in bacteria, fungi, or plants, we have found that the AP profiles of organisms are distinct to a particular organism and can be used to develop growth media which most often not only allow growth but typically increase the rate of growth for an organism. The ratio of the activity of these enzymes enables the design of a mixture of amino acids and select peptides in the composition of a successful growth medium. The AP profile of host plants(s) enabling high density growth of the agent versus low density growth gives further comparisons.