Acidicapsa acidisoli sp. nov., from the acidic soil of a deciduous forest.

A bacterial strain designated strain SK-11 was isolated from the acidic soil of a deciduous forest in the Shirakami Mountains in Japan. Cells of strain SK-11 were aerobic, non-motile, Gram-stain-negative rods, 0.7-1.0 µm in width and 1.0-1.4 µm in length. The pH range for growth was between pH 4.0 and 5.5, with an optimum at pH 5.0. The temperature range for growth was between 10 and 35 °C, with an optimum at around 25-30 °C. Strain SK-11 utilized various carbohydrates as growth substrates as well as yeast extract and protein hydrolysates. The major cellular fatty acids (>10 % of total fatty acid contents) were iso-C15 : 0 (55.4 %), iso-C17 : 0 (16.7 %) and iso-C17 : 1ω9c/10 methyl-hexadecanoic acid (17.7 %). The major respiratory quinone was MK-8. The polar lipids consisted of phosphatidylethanolamine, phosphatidylglycerol, two unidentified phospholipids and an unidentified polar lipid. The DNA G+C content of strain SK-11 was 56.9 %. Phylogenetic analysis based on the 16S rRNA gene sequences revealed that strain SK-11 belonged to the family Acidobacteriaceae within subdivision 1 of the phylum Acidobacteria, and the closest relatives of strain SK-11 were Acidicapsa ligni WH120 and Acidicapsa borealis KA1, with 16S rRNA gene sequence similarities of 96.6 and 96.5 %, respectively. On the basis of the evidence from our polyphasic study, we concluded that strain SK-11 represents a novel species of the genus Acidicapsa, and propose the name Acidicapsa acidisoli sp. nov. The type strain of Acidicapsaacidisolisp nov. is SK-11 (=DSM 100508=NBRC 111227).