Dechloromonas denitrificans sp. nov., Flavobacterium denitrificans sp. nov., Paenibacillus anaericanus sp. nov. and Paenibacillus terrae strain MH72, N2O-producing bacteria isolated from the gut of the earthworm Aporrectodea caliginosa

• Published in: International journal of systematic and evolutionary microbiology Vol. 55; no. 3; pp. 1255 - 1265
• Main Authors: Horn, Marcus A, Ihssen, Julian, Matthies, Carola, Schramm, Andreas, Acker, Georg, Drake, Harold L
• Format: Journal Article
• Language: English
• Published: Reading Soc General Microbiol 01.05.2005; Society for General Microbiology
• Subjects: Aerobiosis; Anaerobiosis; Animals; Bacterial Typing Techniques; Bacteriology; Base Composition; Betaproteobacteria - classification; Betaproteobacteria - cytology; Betaproteobacteria - isolation & purification; Betaproteobacteria - physiology; Biological and medical sciences; Cytochromes c - isolation & purification; Digestive System - microbiology; DNA, Bacterial - chemistry; DNA, Bacterial - isolation & purification; DNA, Ribosomal - chemistry; DNA, Ribosomal - isolation & purification; Endospore-Forming Bacteria - classification; Endospore-Forming Bacteria - cytology; Endospore-Forming Bacteria - isolation & purification; Endospore-Forming Bacteria - physiology; Flavobacterium - classification; Flavobacterium - cytology; Flavobacterium - isolation & purification; Flavobacterium - physiology; Fundamental and applied biological sciences. Psychology; Genes, rRNA; Gentian Violet; Hydrogen-Ion Concentration; Locomotion; Microbiology; Miscellaneous; Molecular Sequence Data; Nitrates - metabolism; Nitrogen - metabolism; Nitrous Oxide - metabolism; Oligochaeta - microbiology; Oxidation-Reduction; Phenazines; Phylogeny; RNA, Bacterial - genetics; RNA, Ribosomal, 16S - genetics; Sequence Analysis, DNA; Systematics; Temperature; Flavobacteriaceae; Paenibacillus; Digestive system; Taxonomy; Gut; Annelida; Oligochaeta; Strain; Earthworm; Flavobacterium; Aporrectodea caliginosa; Bacteria; Invertebrata
• ISSN: 1466-5026; 1466-5034
• DOI: 10.1099/ijs.0.63484-0

1 Department of Ecological Microbiology, University of Bayreuth, 95440 Bayreuth, Germany 2 Electron Microscopy Laboratory, University of Bayreuth, 95440 Bayreuth, Germany Correspondence Harold L. Drake hld{at}uni-bayreuth.de Earthworms emit nitrous oxide (N 2 O) via the activity of bacteria in their gut. Four N 2 O-producing facultative aerobes, ED1 T , ED5 T , MH21 T and MH72, were isolated from the gut of the earthworm Aporrectodea caliginosa . The isolates produced N 2 O under conditions that simulated the microenvironment of the earthworm gut. ED1 T and ED5 T were Gram-negative, motile rods that carried out complete denitrification (i.e. the reduction of nitrate to N 2 ) and contained membranous c -type cytochromes. ED1 T grew optimally at 30 °C and pH 7. ED1 T oxidized organic acids and reduced (per)chlorate, sulfate, nitrate and nitrite. The closest phylogenetic relative of ED1 T was Dechloromonas agitata . ED5 T grew optimally at 25 °C and pH 7. ED5 T grew mainly on sugars, and nitrate and nitrite were used as alternative electron acceptors. The closest phylogenetic relatives of ED5 T were Flavobacterium johnsoniae and Flavobacterium flevense . MH21 T and MH72 were motile, spore-forming, rod-shaped bacteria with a three-layered cell wall. Sugars supported the growth of MH21 T and MH72. Cells of MH21 T grew in chains, were linked by connecting filaments and contained membranous b -type cytochromes. MH21 T grew optimally at 30–35 °C and pH 7·7, grew by fermentation and reduced low amounts of nitrite to N 2 O. The closest phylogenetic relatives of MH21 T were Paenibacillus borealis and Paenibacillus chibensis . Based on morphological, physiological and phylogenetic characteristics, ED1 T (=DSM 15892 T =ATCC BAA-841 T ), ED5 T (=DSM 15936 T =ATCC BAA-842 T ) and MH21 T (=DSM 15890 T =ATCC BAA-844 T ) are proposed as type strains of the novel species Dechloromonas denitrificans sp. nov., Flavobacterium denitrificans sp. nov. and Paenibacillus anaericanus sp. nov., respectively. MH72 is considered a new strain of Paenibacillus terrae . Published online ahead of print on 28 January 2005 as DOI 10.1099/ijs.0.63484-0. The GenBank/EMBL/DDBJ accession numbers for the 16S rRNA gene sequences of Dechloromonas denitrificans ED1 T , Flavobacterium denitrificans ED5 T and Paenibacillus terrae MH72 are AJ318917 , AJ318907 and AJ318910 , respectively. A table of the substrate utilization profiles of earthworm-gut isolates and transmission electron micrographs of strains ED5 T and MH72 are available as supplementary material in IJSEM Online. Present address: Labor L+S AG, Mangelsfeld 4, 97708 Bad Bocklet, Germany. Present address: Department of Microbiology, University of Aarhus, 8000 Aarhus, Denmark.