Conexibacter stalactiti sp. nov., isolated from stalactites in a lava cave and emended description of the genus Conexibacter.

A Gram-positive, strictly aerobic, non-sporulating, motile, rod-shaped bacterium, designated YC2-25T, was isolated from pieces of stalactites collected from a lava cave in Jeju, Republic of Korea. Colonies were circular, smooth, convex and cream to light yellow in colour. A neighbour-joining tree based on 16S rRNA gene sequences indicated that the organism belonged to the genus Conexibacter with the closest relatives being Conexibacter woesei (99.0 % sequence similarity) and Conexibacter arvalis (98.8 %). Meso-Diaminopimelic acid was the diagnostic diamino acid in the cell-wall peptidoglycan. The predominant menaquinone was MK-7(H4). The polar lipids were diphosphatidylglycerol, phosphatidylinositol, two phospholipids and four lipids. The predominant fatty acid was C18 : 1ω9c. The DNA G+C content was 70.3 %. On the basis of distant phenotypic characteristics and DNA-DNA hybridization data, strain YC2-25T (=KCTC 39840T=DSM 103719T) represents a novel species of the genus Conexibacter, for which the name Conexibacter stalactiti sp. nov. is proposed.