Janthinobacterium lividum

Janthinobacterium lividum is an aerobic, gram-negative, soil-dwelling bacterium that has a distinctive dark-violet (almost black) color. This color is due to a compound called violacein, which is produced when glycerol is metabolized as a carbon source. Violacein has anti-bacterial, anti-viral, and anti-fungal properties. Its anti-fungal properties are of particular interest since J. lividum is found on the skin of certain amphibians, including the red-backed salamander (Plethodon cinereus), where it prevents infection by the devastating chytrid fungus (Batrachochytrium dendrobatidis).