(fo″to-kro´mә-jәn) a microorganism whose pigmentation develops as a result of exposure to light. adj., photochromogen´ic., adj.
An organism (e.g. a Mycobacterium) forming pigment only when exposed to light.
photochromogen 1. A microorganism whose pigmentation develops as a result of exposure to light. 2. a mycobacterium that forms yellow or orange colonies when grown in the light.