Summary A total of twenty aerobic endospore-forming bacilli, isolated from marine
invertebrates and sea water of different areas of the Pacific Ocean, were taxonomically
characterized. Most of the bacilli (11 strains) of marine origin belonged to the species
Bacillus subtilis, according to their phenotypic characteristics, antibiotic susceptibility
profiles, and fatty acids patterns. A group of four alkaliphilic strains formed a separate
cluster that was tentatively classified as B. horti. One isolate, KMM 1717, associated
with a sponge from the Coral Sea was identified as B. pumilus. Two strains, Bacillus
KMM 1916 and KMM 1918, showed antibiotic sensitivity profiles similar to B.
licheniformis, but they had a distinct fatty acid composition and peculiar phenotypic
traits. The taxonomic affiliation of KMM 1810 and KMM 1763 remained unclear
since their fatty acid composition and antibiotic sensitivity patterns were not resembled
with none of these obtained for Bacillus strains