Pleomorphobacterium xiamenense gen. nov., sp nov., a moderate thermophile isolated from a terrestrial hot spring

An aerobic, motile, moderately thermophilic rod, designated strain CLWT, was isolated from a terrestrial hot spring in an exposition garden in Xiamen City, Fujian Province, the People's Republic of China. Strain CLWT formed beige, dry colonies on solid 2216E medium and flocks in liquid medium. Cells were Gram-stain-negative, short rods (1.0-3.0 mu m long and 0.4-0.6 mu m wide) with six or more polar flagella. The temperature and pH for growth of strain CLWT were 28-65 degrees C (optimum, 50-58 degrees C) and pH 5.5-9.5 (optimum, pH 6.0-8.0). Growth occurred in the presence of 0.3-6.0% NaCl (optimum 2.5-4.5 %). Phylogenetic analysis based on 16S rRNA gene sequences showed that the closest relative of the isolate was Amaricoccus kaplicensis Ben 101(T) (94.3 % sequence similarity). The DNA G+C content of strain CLWT was 72.2 mol%. The respiratory quinone was ubiquinone 10. The predominant polar lipids consisted of phosphatidylglycerol and phosphatidylethanolamine. The major fatty acids (>10%) were summed feature 8 (consisting of C-18:1 omega 7c and/or C-18.1 omega 6c), C-18:1 omega 7c 11-methyl and C-18:0. Based on phylogenetic, physiological and biochemical data and DNA G+C content, strain CLWT is considered to represent a novel species of a new genus in the family Rhodobacteraceae, for which the name Pleomorphobacterium xiamenense gen. nov., sp. nov. is proposed. The type strain of the type species is CLWT (=LMG 26245(T)=CGMCC 1.10808(T)=MCCC 1A06272(T)).