aux·o·troph·ic 
(ôk
′s
ə-tr
ŏf
ĭk, -tr
ōf
ĭk)
adj. Requiring one or more specific substances for growth and metabolism that the parental organism was able to synthesize on its own. Used with respect to organisms, such as strains of bacteria, algae, or fungi, that can no longer synthesize certain growth factors because of mutational changes.
[Greek auxein, to increase; see AUXIN + -TROPHIC.]
aux·otro·phy (ôk-sŏtrə-fē) n.