Downloaded from www.microbiologyresearch.org by IP: 54.237.106.114 On: Fri, 21 Apr 2017 16:31:18 Microbacterium invictum sp. nov., isolated from homemade compost Ivone Vaz-Moreira, 1,2 Ana R. Lopes, 2 Ca ´ tia Faria, 2 Cathrin Spro ¨ er, 3 Peter Schumann, 3 Olga C. Nunes 2 and Ce ´ lia M. Manaia 1 Correspondence Ce ´ lia M. Manaia cmmanaia@esb.ucp.pt 1 Escola Superior de Biotecnologia, Universidade Cato ´ lica Portuguesa, 4200-072 Porto, Portugal 2 LEPAE – Departamento de Engenharia Quı ´mica, Faculdade de Engenharia, Universidade do Porto, 4200-465 Porto, Portugal 3 DSMZ – Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH, Inhoffenstraße 7B, D-38124 Braunschweig, Germany Strain DC-200 T was isolated from homemade compost produced from kitchen refuse and characterized using a polyphasic approach. The isolate was a Gram-positive motile short rod, facultatively aerobic, catalase-positive and oxidase-negative, and was able to grow at 10–37 6C, pH 6.0–9.5 and with up to 5 % of NaCl. The peptidoglycan was of the type B1 alpha and the muramic acid residues were glycolylated. The major fatty acids were anteiso-C 15 : 0 and anteiso- C 17 : 0 . The predominant respiratory menaquinones were MK-11 and MK-12. The G+C content of the genomic DNA was 70 mol%. Based on the analysis of the 16S rRNA gene sequence, the closest phylogenetic neighbours of strain DC-200 T were Microbacterium lacus A5E-52 T (98.7 %) and Microbacterium aoyamense KV-492 T (98.2 %). The phenetic characterization of the isolate supports its inclusion within the genus Microbacterium; however, its distinctive phenotypic features and the results from the 16S rRNA gene sequence analysis and the DNA–DNA hybridization study suggest that the isolate represents a novel species. The name Microbacterium invictum sp. nov. is proposed. The type strain is DC-200 T (5DSM 19600 T 5LMG 24557 T ). Home composting is an ancient process of recycling domestic and agricultural organic waste, which is a mixture of soft ‘green’ domestic residues such as vegetable leaves, fruit skins or potato peelings and dry ‘brown’ material such as dead leaves or dried grass. Decomposition is performed by several micro-organisms, namely fungi and bacteria, that are present in the raw materials and able to survive the environmental stresses and competitive phenomena that occur during composting (Epstein, 1997). This paper reports the characterization of a strain (designated DC- 200 T ) that was isolated from fully decomposed homemade compost. 16S rRNA gene sequence analysis and DNA– DNA hybridization results showed that the strain is a member of the genus Microbacterium but does not belong to any of the more than 50 species currently included in this genus (Euze ´by, 2008). Strain DC-200 T was isolated from homemade compost produced by thermal digestion of kitchen refuse in a wooden domestic composter (1 m 3 ), where temperatures of about 50 u C are reached (Vaz-Moreira et al., 2008). The isolate was purified by subculturing on plate count agar (PCA; Pronadisa) containing (l 21 ): 5 g tryptone, 2.5 g yeast extract, 1 g glucose and 15 g agar. Cultures were incubated at 30 u C and cells were stored at 280 u C in nutrient broth with 15 % (v/v) glycerol for preservation. Colony and cell morphological descriptions, Gram-stain reaction, cytochrome-c oxidase and catalase tests and endospore and motility visualizations were based on the methodologies of Murray et al. (1994) and Smibert & Krieg (1994). Unless otherwise stated, all biochemical and physiological tests were performed as described previously (Vaz-Moreira et al., 2007). Biochemical and nutritional tests were assayed using the API 20E, API 20NE, API 50 CH and API ZYM systems (bioMe ´rieux) following the manufacturer’s instructions, and API 50 CH was inocu- lated with the medium recommended to test acid production and with mineral medium B (Barreiros et al., 2003) supplemented with 4 mM (NH 4 ) 2 SO 4 and 0.5 % yeast extract. Antibiotic susceptibility was assayed as described by Ferreira da Silva et al. (2006). The determination of the genomic DNA G+C content and the analysis of respiratory quinones were performed as described previously (Vaz-Moreira et al., 2007) using the methods of Mesbah et al. (1989) and Tindall (1989), respectively. The cellular fatty acid compositions of strains Abbreviation: MALDI-TOF, matrix-assisted laser-desorption/ionization time-of-flight. The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of strain DC-200 T is AM949677. International Journal of Systematic and Evolutionary Microbiology (2009), 59, 2036–2041 DOI 10.1099/ijs.0.005561-0 2036 005561 G 2009 IUMS Printed in Great Britain