Paenibacillus azotifigens sp nov., a novel nitrogen-fixing bacterium isolated from paddy soil

A nitrogen-fixing bacterium, designated NF2-4-5(T), was isolated from a paddy soil in Anseong City, Korea. Cells of strain NF24- 5(T) were Gram-staining-positive, motile rods and aerobic. Phylogenetic analysis based on 16S rRNA gene sequence comparison revealed that the strain formed a distinct lineage within the genus Paenibacillus and was closely related to Paenibacillus graminis RSA19(T) (98.7 %), Paenibacillus jilunlii Be17(T) (98.6 %), Paenibacillus salinicaeni LAM0A28(T) (98.6 %) and Paenibacillus riograndensis SBR5(T) (98.6 %). Growth of strain NF2-4-5(T) occurs at temperatures of 18-37 degrees C, at pH 6.0-8.5 and between 0.5% and 2% NaCl (w/v). The only respiratory quinone was MK-7. The cell wall peptidoglycan of strain NF2-4-5(T) contained meso-diaminopimelic acid. The main cellular fatty acids were C-16 : 0 and anteiso-C-15 : 0. The major polar lipids were diphosphatidylglycerol (DPG), phosphatidylglycerol (PG) and phosphatidylethanolamine (PE). The DNA G+C content was 56.36 mol%. The DNA-DNA hybridization relatedness between strain NF2-4-5(T) and four reference strains, Paenibacillus graminis RSA19(T), Paenibacillus jilunlii Be17(T), Paenibacillus sonchi X19-5(T) and Paenibacillus riograndensis SBR5(T), was 22.0 +/- 0.3, 20.1 +/- 0.7, 18.3 +/- 0.3 and 12.6 +/- 0.5 %, respectively. The phenotypic, phylogenetic and chemotaxonomic results indicate that the strain NF2-4-5(T) represents a novel species of the genus Paenibacillus, for which the name Paenibacillus azotifigens sp. nov. is proposed. The type strain is NF2-4-5(T) (=KACC 18967(T) = LMG 29963(T)).