A novel species of thermoacidophilic archaeon, Sulfolobus yangmingensis sp. nov.

A novel microbe was isolated from a geothermal vent in Yang-Ming National Park in northern Taiwan. This spherical microbe with mean cell diameter of 1.1 +/- 0.2 microns is a facultatively chemolithoautotrophic archaeon that grows on elemental sulfur and reduced sulfur compounds. The optimal pH and temperature for growth are 4.0 (pH range 2.0-6.0) and 80 degrees C (temperature range 65-95 degrees C). Its membranes contain the lipids calditoglycerocaldarchaeol and caldarchaeol, which are common to other members of the Sulfolobaceae. Like Sulfolobus acidocaldarius, Sulfolobus shibatae and Sulfolobus solfataricus, the new isolate utilizes sugars and amino acids effectively as sole carbon sources. The G + C content of the genomic DNA was 42 mol%. DNA of the isolate hybridized weakly to the DNA of other Sulfolobus species. Phylogenetic analysis of the 16S rRNA indicated that the new isolate represents a deep branch within the genus Sulfolobus. On the basis of these properties, the new isolate appears to represent a new species of Sulfolobus, for which the name Sulfolobus yangmingensis sp. nov. is proposed. The type strain is strain YM1T.