Bacillus catenulatus sp. nov., an alkalitolerant bacterium isolated from a soda lake

Abstract

Two novel (18C^T and 6C) Gram-stain-positive, rod shaped, motile and endospore-forming bacterial strains were isolated from Lonar soda lake, India. Based on 16S rRNA gene sequence analysis, strains 18C^T and 6C were identified as belonging to the class Firmibacteria, and were most closely related to Bacillus cohnii KCTC 3572^T (99.3 and 99.9%, respectively), Bacillus zhanjiangensis KCTC 13713^T (97.4 and 98.0%, respectively), Bacillus halmapalus LMG 17950^T (97.0 and 97.6%, respectively) and other members in the genus Bacillus (<97.0%). However, the DNA–DNA relatedness between 18C^T and 6C and B. cohnii KCTC 3572^T (49.6 ± 0.9 and 51.6 ± 0.7, respectively), B. zhanjiangensis KCTC 13713^T (42.9 ± 0.8 and 47.1 ± 0.3, respectively) and B. halmapalus LMG 17950^T (39.9 ± 0.8 and 40.8 ± 0.3, respectively) indicated that the novel strains were distantly related to these strains. Further, the high 16S rRNA gene sequence similarity (100%) and DNA–DNA relatedness (90 ± 5%) suggested that strains 18C^T and 6C were members of a genomospecies. The strains grew optimally at a pH of 7.5 with 2–3% (w/v) NaCl and temperature of 37 °C. Strains 18C^T and 6C were catalase and oxidase negative. The cell wall of strain 18C^T contained meso-diaminopimelic acid as the diagnostic diamino acid, which was in contrast with its nearest neighbour B. cohnii KCTC 3572^T, which contained ornithine and aspartic acid. Polar lipids include diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), phosphatidylethanolamine (PE), an unknown phospholipid (PL) and three unknown lipids (L1-3). The predominant isoprenoid quinone was MK-7. iso-C_15:0 (32.5%) was the predominant fatty acid and significant proportions of anteiso-C_15:0 (19.5%), C_16:0 (11.5%), iso-C_17:0 (9.5%) and anteiso-C_17:0 (6.3%) were also detected. The DNA G + C content of strains 18C^T and 6C were 39.3 and 39.2 mol%, respectively. The results of molecular, biochemical and chemotaxonomic tests showed a clear differentiation of strains 18C^T and 6C from all other members of the genus Bacillus, for which the name Bacillus catenulatus sp. nov. is proposed. The type strain is 18C^T (=KCTC 33781^T = CGMCC 1.15475^T).

from # & - All via ola Kala on Inoreader http://ift.tt/2tHhauc