Kluyveromyces nonfermentans sp. nov., a new yeast species isolated from the deep sea

1 Deep-sea Microorganism Research Group, Japan Marine Science and Technology Center (JAMSTEC), 2–15 Natsushima-cho, Yokosuka 237–0061, Japan 2 Japan Collection of Microorganisms, The Institute of Physical and Chemical Research (RIKEN), Wako, Saitama 351–0198, Japan Author for correspondence: Takahiko Nagahama. Tel: +81 468 67 5556. Fax: +81 468 66 6364. e-mail: nagahama{at}jamstec.go.jp ABSTRACT Eleven strains of a new species of the genus Kluyveromyces , characterized as having evanescent asci and Q-6 as the major ubiquinone, were isolated from sediments, a clam and a crab collected at depths of 1000–2000 m in Suruga Bay and Sagami Bay, Japan. A phylogenetic tree based on small-subunit (18S) rRNA gene sequences placed these isolates into a cluster of Kluyveromyces. DNA complementarity and phylogenetic trees of internal transcribed spacer (ITS) regions and 5·8S rRNA genes showed that the isolates are closely related to Kluyveromyces aestuarii , but that these two species are genetically distinct. The isolates are described as Kluyveromyces nonfermentans sp. nov. Because this species lacks the fermentative ability considered to be an important criterion for the genus Kluyveromyces , the definition of the genus has been emended. The type strain of K. nonfermentans is strain SY-33 T (= JCM 10232 T ). Key Words: Kluyveromyces nonfermentans sp. nov. • 18S rDNA • 5·8S rDNA • internal transcribed spacer • deep-sea isolates The DDBJ accession numbers for the 18S rDNA sequences reported in this paper are AB011507 –AB011510 , AB011512 –AB011521 and AB012264 .