Flavobacterium lacus sp. nov., isolated from a high-altitude lake, and emended description of Flavobacterium filum.

Two Gram-stain-negative, non-motile, rod-shaped bacterial strains, designated NP180(T) and NR80, were isolated from water of Nam Co Lake, located in Tibet, China. Growth of strains NP180(T) and NR80 occurred at 4-25 °C and at pH 6.5-10.0 (optima, 15-20 °C and pH 7.5-8.5). The 16S rRNA gene sequence similarity to the phylogenetically closest related strains, Flavobacterium filum EMB 34(T), F. ponti GSW-R14(T) and F. gelidilacus LMG 21477(T), was 95.1, 94.8 and 94.6 %, respectively. The predominant fatty acids were iso-C15 : 0, iso-C15 : 1 G, iso-C17 : 0 3-OH and summed feature 9 (comprising iso-C17 : 1ω9c and/or 10-methyl C16 : 0). The major menaquinone of the two strains was menaquinone 6 (MK-6). Phosphatidylethanolamine, one unidentified aminolipid and one unidentified lipid were the major polar lipids in both strains. The G+C contents of the genomic DNA were 34.9 and 35.1 mol%, respectively, for strains NP180(T) and NR80. DNA-DNA relatedness between strains NP180(T) and NR80 was 99 %, indicating that they belong to the same species. According to phylogenetic inference and phenotypic characteristics, a novel species, Flavobacterium lacus sp. nov., is proposed. The type strain is NP180(T) ( = CGMCC 1.12504(T) = NBRC 109715(T)). An emended description of Flavobacterium filum is also provided.