Meiothermus hypogaeus sp. nov., a moderately thermophilic bacterium isolated from a hot spring

Abstract

A novel moderately thermophilic, red-pigmented bacterium, designated strain AZM34c11T, was isolated from the bottom of a 1000 m-deep drilled well located in a Japanese hot spring. Cells were Gram-negative and grew optimally at 50 °C, at pH 7.6 and with 0–0.3 % (w/v) NaCl. Analysis of the 16S rRNA gene sequence revealed that the isolate belonged to the genusMeiothermus. Levels of 16S rRNA gene sequence similarity between strain AZM34c11Tand the type strains of recognizedMeiothermusspecies were 88.2–94.8 %. Strain AZM34c11Twas distinguished from recognizedMeiothermusspecies by its cellular fatty acid profile: iso-C16 : 0was one of the predominant components and hydroxy fatty acids were present only in trace amounts. The strain could also be differentiated based on its growth substrate preferences and characteristic enzyme reactions. On the basis of these results, strain AZM34c11Tis considered to represent a novel species of the genusMeiothermus, for which the nameMeiothermus hypogaeussp. nov. is proposed. The type strain is AZM34c11T( = NBRC 106114T = DSM 23238T).