Niveispirillum Lacus Sp Nov., Isolated From Cyanobacterial Aggregates In A Eutrophic Lake

A bacterial strain, 1-14(T), was isolated from cyanobacterial aggregates in a eutrophic lake, Taihu Lake, China. Cells were observed to be slightly curved, rod-shaped, aerobic and Gram-stain-negative. Optimal growth occurred at pH 7.0 (range: 5.0-9.0), 28 degrees C (range: 20-32 degrees C) and 0% (w/v) NaCl (range: 0-1.0 %) in R2A broth. No growth is observed at 37 degrees C. The cells were found to be positive for oxidase and catalase activities. The major respiratory quinone was ubiquinone Q-10. The major fatty acids (> 10 %) were identified as C-18:1 omega 6c/C-18:1 omega 7c, C-16:0 3-OH and C-18:1 2-OH. The major polar lipids were found to consist of phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylglycerol and phosphatidylcholine. Within the genus Niveispirillum, strain 1-14(T) was most closely related to Niveispirillum cyanobacteriorum TH16(T) (98.3% 16S rRNA gene sequence similarity), followed by Niveispirillum irakense DSM 11586(T) (97.8 %) and Niveispirillum fermenti CC-LY736(T) (97.0 %). The genomic G+C content of strain 1-14(T) was 62.2 mol% based on total genome calculations. Genes coding for light-harvesting complexes LHI and LHII, and a photosynthetic reaction centre were detected in the genome. Average nucleotide identities and digital DNA-DNA hybridizations for complete genomes ranged from 76.4 to 83.5 and from 21.5 to 27.4% between strain 1-14(T) and strains within the genus Niveisprillum. The phenotypic, chemotaxonomic and phylogenetic properties, and genome analysis suggested that strain 1-14(T) represents a novel species within the genus Niveispirillum, for which the name Niveispirillum lacus sp. nov. is proposed. The type strain is 1-14(T) (= CGMCC 1.12980(T) = LMG 28363(T)).