Sphingomonas carri sp. nov., isolated from a car air-conditioning system

Abstract

A Gram-stain-negative, yellow-pigmented bacterial strain, designated PR0302^T, was isolated from a car evaporator core collected in Korea. The cells were strictly aerobic, non-spore-forming and rod-shaped. The strain grew at 15-37 °C (optimum, 25 °C), at pH 6.0-8.0 (optimum, 7.0) and in the presence of 0-1 % (w/v) NaCl. Phylogenetically, the strain was closely related to members of the genus Sphingomonas(97.04-91.22 % 16S rRNA gene sequence similarities) and showed the highest sequence similarity of 97.04 % to Sphingomonas kyeonggiensis THG-DT81^T. It contained C16 : 0, summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c) and C14 : 0 2-OH as the predominant fatty acids and Q-10 as the major ubiquinone. The predominant polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine and sphingoglycolipid. The major polyamine was sym-homospermidine. The serine palmitoyl transferase gene (spt) was detected and sphingolipid synthesis was confirmed. The mean DNA G+C content of the strain was 67.8±0.5 mol%. DNA-DNA relatedness between strain PR0302^T and closely related type strains of Sphingomonas species was less than 30 %. The low levels of DNA-DNA relatedness identified strain PR0302^T as a member of a novel species in the genus Sphingomonas. Based on phenotypic, genotypic and chemotaxonomic data, strain PR0302^T represents a novel species in the genus Sphingomonas, for which the name Sphingomonas carri sp. nov. is proposed. The type strain is PR0302^T (=KACC 18487^T=NBRC 111532^T).

Keywords: Sphingomonas carri; car evaporator core; novel species; polyphasic taxonomy.