Caenibacterium thermophilum gen. nov., sp. nov., isolated from a thermophilic aerobic digester of municipal sludge

Abstract

A bacterial strain, N2-680 T (=DSM 15264 T =LMG 21760 T ), isolated from a thermophilic aerobic digester of municipal sludge, was characterized with respect to its morphology, physiology and taxonomy. Phenotypically, the isolate was a Gram-negative rod with a polar flagellum, catalase-and oxidase-positive, containing cytoplasmic inclusions of poly-b-hydroxybutyrate and had an optimal growth temperature of about 47 6C. Strain N2-680 T was unable to reduce nitrate and could use organic acids, amino acids and carbohydrates as single carbon sources. Chemotaxonomic analysis revealed that ubiquinone 8 was the major respiratory quinone of this organism and that phosphatidylethanolamine and phosphatidylglycerol were the major polar lipids. At 50 6C, the major components in fatty acid methyl ester analysis were C 16 : 0 and cyclo-C 17 : 0 . The highest 16S rDNA sequence identity of isolate N2-680 T was to Leptothrix mobilis and Ideonella dechloratans (95?7 %) and to Rubrivivax gelatinosus and Aquabacterium commune (95?6 %). 16S rDNA sequence similarities to species of two related thermophilic genera, Caldimonas manganoxidans and Tepidimonas ignava, were lower (93?6 and 94?7 %). On the basis of phylogenetic analyses and physiological and chemotaxonomic characteristics, it is proposed that isolate N2-680 T represents a new genus and species, for which the name Caenibacterium thermophilum gen. nov., sp. nov. is proposed.

Tepidiphilus margaritifer gen. nov., sp. nov., isolated from a thermophilic aerobic digester

“…Hydrogenase activity was determined on the basis of the descriptions of Aragno & Schlegel (1992) and Stöhr et al (2001) as described by Manaia et al (2003). The nutritional pattern was characterized using the API 50CH system and a defined medium (medium B) as described by Manaia et al (2003). Chemolithoautotrophic growth, the use of H 2 as an energy source and the ability to use sulfur or thiosulfate as electrons donors were tested as described by Manaia et al (2003).…”

“…Enzymic activities were tested using the API ZYM system by following the instructions of the manufacturer (bioMérieux). Hydrogenase activity was determined on the basis of the descriptions of Aragno & Schlegel (1992) and Stöhr et al (2001) as described by Manaia et al (2003). The nutritional pattern was characterized using the API 50CH system and a defined medium (medium B) as described by Manaia et al (2003).…”

“…The 16S rRNA gene sequence was determined after PCR amplification as described by Manaia et al (2003). The nucleotide sequence was compared with reference 16S rDNA sequences in the EMBL database using the FASTA program (Pearson & Lipman, 1988) and subsequently aligned with reference sequences included in the ARB package (http://www.arb-home.de).…”

“…Colony and cell morphology, Gram-staining reaction, production of spores, accumulation of poly-b-hydroxybutyrate (PHB) granules, the number and position of flagella and the temperature range for growth were examined as described by Manaia et al (2003).…”

“…The nutritional pattern was characterized using the API 50CH system and a defined medium (medium B) as described by Manaia et al (2003). Chemolithoautotrophic growth, the use of H 2 as an energy source and the ability to use sulfur or thiosulfate as electrons donors were tested as described by Manaia et al (2003). The ability to grow in the absence of a source of combined nitrogen was tested using medium A without ammonium sulfate, under aerobic conditions or under an N 2 atmosphere with nitrate as the electron acceptor.…”