Tessaracoccus bendigoensis gen. nov., sp. nov., a Gram-positive coccus occurring in regular packages or tetrads, isolated from activated sludge biomass

1 Biotechnology Research Centre, La Trobe University, Bendigo, VIC 3550, Australia 2 Faculty of Science, School of Biomolecular and Biomedical Sciences, Griffith University, Nathan, Brisbane, QLD 4111, Australia 3 Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH, Aussenstelle Jena, Beutenbergstrasse 11, D-07745 Jena, Germany 4 CRC Freshwater Ecology, Murray-Darling Freshwater Research Centre, PO Box 921, Albury, NSW 2640, Australia Author for correspondence: R. J. Seviour. Tel: +61 354 447459. Fax: +61 354 447476. e-mail: r.seviour{at}latrobe.edu.au ABSTRACT An isolate of a Gram-positive bacterium, designated strain Ben 106 T , was obtained in pure culture by micromanipulation of a biomass sample obtained from a laboratory-scale sequencing batch reactor. This isolate grew axenically as cocci or clusters of cocci arranged in regular tetrads and was morphologically similar to the dominant organism observed in the biomass. This morphology resembled that of some Gram-positive and -negative bacteria and the so-called ‘G-bacteria’ commonly seen in activated sludge samples. Strain Ben 106 T is a non-motile, facultative anaerobe. It is oxidase-negative, catalase-positive and is capable of reducing nitrate. This organism can grow between 20 and 37 °C, with an optimum temperature of 25 °C. The pH range for growth is between 6.0 and 9.0, with an optimum pH of 7.5. The isolate stained positively for intracellular polyphosphate granules. The diagnostic diamino acid of the peptidoglycan is LL-diaminopimelic acid (LL-A 2 pm) with a glycine moiety at position 1 of the peptide subunit, which characterizes the presence of a rare peptidoglycan (type A3- ). Two menaquinones, MK-9(H 4 ) and MK-7(H 4 ), are present and the main cellular fatty acid is 12-methyltetradecanoic acid. The G+C content is 74 mol%. From phenotypic characteristics and 16S rDNA sequence analysis, the isolate differed sufficiently from its closest phylogenetic relatives, namely Propionibacterium propionicum, Propioniferax innocua, Friedmanniella antarctica, Luteococcus japonicus and Microlunatus phosphovorus in the A1 subdivision of the Gram-positive bacteria (i.e. Firmicutes with a high G+C content), suborder Propionibacterineae , to be placed in a new genus, Tessaracoccus, as Tessaracoccus bendigoensis gen. nov., sp. nov. The type strain is Ben 106 T (= ACM 5119 T ). Key Words: Tessaracoccus bendigoensis • activated sludge • Gram-positive coccus • Propionibacteriaceae • G-bacteria The GenBank