TABLE 3.

Phenotypic characteristics of the six representative isolates obtained from the biooxidation reactors

GroupRepresentative isolate(s)Colony morphologyCellular morphologyCarbon metabolismOxidation of:Preliminary identification
Fe2+FeS2S4O62−
IMT1, MT2Domed, entire, off-whiteMotile straight rodsAutotrophic+A. caldus
IIMT6Flat, entire, small, orange-brown, Fe3+ encrustedMotile curved rodsAutotrophic++Leptospirillum
IIINCDomed, irregular, orange-brown centers with off-white peripheries (fried egg-like)Nonmotile sporulating rodsMixotrophic+a+a+aSulfobacillus
IVMT16, MT17Raised, entire, small, fried egg-likeIrregular cocci to pleomorphicHeterotrophic+a+a+aArchaea
  • a Oxidation only in yeast extract-amended cultures.