Tetrathiobacter mimigardefordensis sp. nov., isolated from compost, a betaproteobacterium capable of utilizing the organic disulfide 3,3'-dithiodipropionic acid

1 Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, Corrensstraße 3, 48149 Münster, Germany 2 Laboratory of Microbiology, Department of Biochemistry, Physiology and Microbiology, University of Ghent, K. L. Ledeganckstraat 35, 9000 Ghent, Belgium Correspondence Alexander Steinbüchel steinbu{at}uni-muenster.de In this study, a novel betaproteobacterium, strain DPN7 T , was isolated under mesophilic conditions from compost because of its capacity to utilize the organic disulfide 3,3'-dithiodipropionic acid. Analysis of the 16S rRNA gene sequence of strain DPN7 T revealed 98.5 % similarity to that of Tetrathiobacter kashmirensis LMG 22695 T . Values for sequence similarity to members of the genera Alcaligenes , Castellaniella and Taylorella , the nearest neighbours of the genus Tetrathiobacter , were about 95 % or less. The DNA G+C content of strain DPN7 T was 55.1 mol%. The level of DNA–DNA hybridization between strain DPN7 T and T. kashmirensis LMG 22695 T was 41 %, whereas it was much lower between strain DPN7 T and Alcaligenes faecalis LMG 1229 T (7 %) or Castellaniella defragrans LMG 18538 T (5 %). This genotypic divergence was supported by differences in biochemical and chemotaxonomic characteristics. For this reason, and because of the differences in the protein and fatty acid profiles, strain DPN7 T should be classified within a novel species of Tetrathiobacter , for which the name Tetrathiobacter mimigardefordensis sp. nov. is proposed. The type strain is strain DPN7 T (=DSM 17166 T =LMG 22922 T ). Abbreviations: DTDP, 3,3'-dithiodipropionic acid The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of strain DPN7 T is AY880023 . A phase-contrast micrograph of cells of strain DPN7 T is available as supplementary material in IJSEM Online. Present addresss: Massachusetts Institute of Technology, Department of Chemical Engineering, 77 Massachusetts Avenue 56-422, Cambridge, MA 02139, USA.