Spirosoma lacussanchae sp. nov., a phosphate-solubilizing bacterium isolated from a freshwater reservoir

A phosphate-solubilizing bacterium, designated CPCC 100624T, was isolated from a freshwater reservoir in south-west China. The 16S rRNA gene sequence comparison of strain CPCC 100624T with the available sequences in the GenBank database showed that the isolate was closely related to members of the genus Spirosoma. In the phylogenetic tree based on 16S rRNA gene sequences, strain CPCC 100624T formed a stable phylogenetic subclade with Spirosoma soli MIMBbqt12T within the genus Spirosoma, which indicated that strain CPCC 100624T could be identified as a member of the genus Spirosoma. The strain grew at 10-40 °C (optimum 30 °C), at pH 6.5-8.0 (optimum pH 7.0-7.5) and in the presence of 0-5 % (w/v) NaCl (optimum 0-1 %). MK-7 was detected as the main menaquinone, with a minor amount of MK-7(H6) in its menaquinone system. Cells contained summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c), C16 : 1ω5c and iso-C15 : 0 as the major fatty acids. The polar lipids of strain CPCC 100624T contained phosphatidylethanolamine, one unidentified aminolipid, two aminophospholipids and three unidentified lipids. The genomic DNA G+C content was 49.3 mol%. On the basis of the above taxonomic data and differences in physiological characteristics from the closely related type strains, strain CPCC 100624T represents a novel species of the genus Spirosoma, for which the name Spirosoma lacussanchae sp. nov. is proposed. The type strain is CPCC 100624T (=NBRC 111852T=DSM 101771T).