Description ofThermococcus kodakaraensissp. nov., a well studied hyperthermophilic archaeon previously reported asPyrococcussp. KOD1

Abstract

A hyperthermophilic archaeal strain, KOD1, isolated from a solfatara on Kodakara Island, Japan, has previously been reported asPyrococcussp. KOD1. However, a detailed phylogenetic tree, made possible by the recent accumulation of 16S rRNA sequences of various species in the order Thermococcales, indicated that strain KOD1 is a member of the genusThermococcus. We performed DNA–DNA hybridization tests against species that displayed high similarity in terms of 16S ribosomal DNA sequences, includingThermococcus peptonophilusandThermococcus stetteri. Hybridization results and differences in growth characteristics and substrate utilization differentiated strain KOD1 fromT. peptonophilusandT. stetteriat the species level. Our results indicate that strain KOD1 represents a new species ofThermococcus, which we designate asThermococcus kodakaraensisKOD1 sp. nov.