Acidithiobacillus acidisediminis sp. nov., an acidophilic sulphur- oxidizing chemolithotroph isolated from acid mine drainage sediment

Strain S30A2 T , isolated from the acid mine drainage sediment of Mengzi Copper Mine, Yunnan, is proposed to represent a novel species of the sulphur- oxidizing genus Acidithiobacillus . Cells were Gram- stain- negative, non- endospore forming, highly motile with one or two monopolar flagella and rod- shaped. The strain was mesophilic, growing at 30-50 degrees C (optimum, 38 degrees C), acidophilic, growing at pH 2.0-4.5 (optimum, pH 2.5), and tolerant of 0-4 % (w/v; 684 mol l -1 ) NaCl. The 16S rRNA gene - based sequence analysis showed that strain S30A2 T belongs to the genus Acidithiobacillus and shows the largest similarity of 96.6 % to the type strain Acidithiobacillus caldus KU T . The genomic DNA G+C content of strain S30A2 T was 59.25 mol%. The average nucleotide identity ANIb and ANIm values between strain S30A2 T and A. caldus KU T were 70.95 and 89.78 %, respectively and the digital DNA-DNA hybridization value was 24.9 %. Strain S30A2 T was strictly aerobic and could utilize elementary sulphur and tetrathionate to support chemolithotrophic growth. The major cellular fatty acid of S30A2 T was C 19:1 omega 7 c . The respiratory quinones were ubiquinone- 8 and ubiquinone- 7. Based upon its phylogenetic, genetic, phenotypic, physiologic and chemotaxonomic characteristics, strain S30A2 T is considered to represent a novel species of the genus Acidithiobacillus , for which the name Acidithiobacillus acidisediminis sp. nov. is proposed. The type strain is S30A2 T (=CGMCC 1.17059 T =KCTC 72580 T ).