Downloaded from www.microbiologyresearch.org by IP: 54.237.57.119 On: Thu, 21 Apr 2016 09:52:32 International Journal of Systematic and Evolutionary Microbiology (2001), 51, 171–177 Printed in Great Britain Reclassification of Desulfobacterium phenolicum as Desulfobacula phenolica comb. nov. and description of strain Sax T as Desulfotignum balticum gen. nov., sp. nov. Jan Kuever, 1 Martin Ko  nneke, 1 Alexander Galushko 2 and Oliver Drzyzga 3 Author for correspondence : Jan Kuever. Tel : 49 421 2028 734. Fax: 49 421 2028 580. e-mail : jkuevermpi-bremen.de 1 Max-Planck-Institute for Marine Microbiology, Department of Microbiology, Celsiusstrasse 1, D-28359 Bremen, Germany 2 Fakulta  t fu  r Biologie, Universita  t Konstanz, Postfach 5560, D-78457 Konstanz, Germany 3 University of Bremen, Center for Environmental Research and Technology (UFT), Department of Marine Microbiology, Leobener Strasse, D-28359 Bremen, Germany A mesophilic, sulfate-reducing bacterium (strain Sax T ) was isolated from marine coastal sediment in the Baltic Sea and originally described as a ‘ Desulfoarculus ’ sp. It used a large variety of substrates, ranging from simple organic compounds and fatty acids to aromatic compounds as electron donors. Autotrophic growth was possible with H 2 , CO 2 and formate in the presence of sulfate. Sulfate, thiosulfate and sulfite were used as electron acceptors. Sulfur and nitrate were not reduced. Fermentative growth was obtained with pyruvate, but not with fumarate or malate. Substrate oxidation was usually complete leading to CO 2 , but at high substrate concentrations acetate accumulated. CO dehydrogenase activity was observed, indicating the operation of the CO dehydrogenase pathway (reverse Wood pathway) for CO 2 fixation and complete oxidation of acetyl-CoA. The rod-shaped cells were 08–10 μm wide and 15–25 μm long. Spores were not produced and cells stained Gram-negative. The temperature limits for growth were between 10 and 42 SC (optimum growth at 28–32 SC). Growth was observed at salinities ranging from 5 to 110 g NaCl l 1 , with an optimum at 10–25 g NaCl l 1 . The GMC content of the DNA was 624 mol %. Vitamins were required for growth. Based on the 16S rRNA gene sequence, strain Sax T represents a new genus within the δ-subclass of the Proteobacteria. The name Desulfotignum balticum gen. nov., sp. nov. is proposed. After the 16S rDNA sequences of all members of the genus Desulfobacterium were published (GenBank accession nos. AJ237601–AJ237604, AJ237606, AJ237607), the need to reclassify most members of the genus Desulfobacterium became obvious due to their strong phylogenetic affiliation to other genera. Here, we propose to reclassify Desulfobacterium phenolicum as Desulfobacula phenolica comb. nov. Desulfotignum balticum, Desulfobacterium phenolicum and Desulfobacula toluolica contain cellular fatty acids which have so far only been found in members of the genus Desulfobacter. Keywords : Desulfobacula, Desulfotignum, marine sulfate-reducing bacterium, complete oxidation, FAME INTRODUCTION Among the sulfate-reducing bacteria of the δ-subclass of the Proteobacteria several marine isolates are known ................................................................................................................................................. Abbreviations : FAME, fatty acid methyl ester ; HMN, 2,2,4,4,6,8,8- heptamethylnonane. The GenBank accession number for the nearly complete 16S rRNA sequences of strain Sax T (DSM 7044 T ) is AF233370. to grow on a large variety of aromatic compounds, including phenolic compounds and toluene. They were originally classified as members of the genera Desulfo- bacterium and Desulfobacula (Bak & Widdel, 1986a, b ; Brysch et al., 1987; Rabus et al., 1993, 2000). Besides the use of various aromatic compounds, members of the genus Desulfobacula are characteristically restric- ted to the utilization of short-chain fatty acids and simple organic compounds as electron donors ; 01545  2001 IUMS 171