Paraliobacillus zengyii sp. nov., a slightly halophilic and extremely halotolerant bacterium isolated from Tibetan antelope faeces.

Abstract

Two rod-shaped, slightly halophilic and extremely halotolerant bacterial strains (X-1125T and X-1174), which were Gram-stain-positive, facultatively anaerobic and motile with peritrichous flagella, were isolated from the faeces of Tibetan antelopes. Their optimal temperature, NaCl concentration and pH for growth were 28 °C, 3 % (w/v) NaCl and pH 7.5, respectively. Based on the results of 16S rRNA gene sequences, and phylogenetic and phylogenomic analyses, their nearest phylogenetic neighbours were Paraliobacillussediminis KCTC 33762T (98.4 % similarity), Paraliobacillusquinghaiensis CGMCC 1.6333T (96.9 %) and Paraliobacillusryukyuensis NBRC 100001T (95.9 %) while the 16S rRNA genes of strains X-1125T and X-1174 were highly similar (99.7 %) to each other. The polar lipids comprised diphosphatidylglycerol, two unidentified phospholipids and four unidentified lipids. MK-7 was the sole menaquinone (100 %). The cell wall contained alanine, glycine, glutamic acid and meso-diaminopimelic acid. The major fatty acids (>9 %) were anteiso-C15 : 0, anteiso-C17 : 0 and C16 : 1ω11c. The in silico DNA-DNA hybridization value between strains X-1125T and X-1174 was 97.8 % (well above the species threshold), but their values were lower than the 70 % threshold with the three closely related type strains. Strains X-1125T and X-1174 had DNA G+C contents (mol%) of 35.2 and 35.1 %, respectively. Based on the presented data, strains X-1125T and X-1174 hereby represent a novel species of the genus Paraliobacillus, for which the name Paraliobacillus zengyii sp. nov. is proposed. The type strain is X-1125T (=DSM 107811T=CGMCC 1.16464T).