General Information: This symbiotic and thermophilic bacterium was discovered by screening for thermostable tryptanophases in Japanese compost. Cultured growth of this organism requires the presence of another bacterial species, such as a Bacillus or Escherichia coli, which provides diffusable metabolites required for its growth. Pure cultures can be obtained by growing Symbiobacterium thermophilum in a bioreactor, separated from its symbiotic counterpart by a dialysis membrane. Because of its symbiotic nature, it cannot be cultured with conventional methods. Despite a negative reaction for gram stain, this species is placed with the gram-positive bacteria based on 16s phylogenetic analysis.