Lacimicrobium alkaliphilum gen. nov., sp. nov., a member of the family Alteromonadaceae isolated from a salt lake.

Abstract

A Gram-stain-negative, facultatively aerobic bacterium, strain X13M-12T, was isolated from a salt lake (Lake Xiaochaidan) in the Qaidam basin, Qinghai Province, PR China. Cells of strain X13M-12T were slightly curved, rod-shaped, 0.5-0.8 μm wide and 1.2-2.3 μm long, and motile by means of a polar flagellum. Strain X13M-12T was catalase- and oxidase-positive. Growth was observed in the presence of 0-15.0 % (w/v) NaCl (optimum 3.0-5.0 %), and at 4-40 °C (optimum 25-30 °C) and pH 6.0-11.0 (optimum pH 8.5). Strain X13M-12T contained Q-8 as the sole respiratory quinone, and phosphatidylglycerol and phosphatidylethanolamine as the major polar lipids. The major cellular fatty acids (>10 % of totals) were C16 : 0, C16 : 1ω7c and/or C16 : 1ω6c, and C18 : 1ω7c and/or C18 : 1ω6c. Phylogenetic analysis, based on 16S rRNA gene sequences, showed that strain X13M-12T belonged to the family Alteromonadaceae and formed a distinct lineage, showing low gene sequence similarities to closely related genera: Bowmanella, Aestuariibacter and Salinimonas (16S rRNA gene sequence similarities, 93.0-93.1 %, 92.3-93.1 % and 92.6-92.7 %, respectively). In addition, strain X13M-12T showed < 92.7 % gene sequence similarities to other species of the family Alteromonadaceae. The DNA G+C content of strain X13M-12T was 49 mol% (Tm). Based on the data presented above, strain X13M-12T is considered to represent a novel genus and species of the family Alteromonadaceae, for which the name Lacimicrobium alkaliphilum gen. nov., sp. nov. is proposed. The type strain is X13M-12T ( = CGMCC 1.12923T = KCTC 42674T).