NATRONOCOCCUS AMYLOLYTICUS SP-NOV, A HALOALKALIPHILIC ARCHAEON

The alpha-amylase-producing haloalkaliphilic archaeon Natronococcus sp, strain Ah-36(T) (T = type strain) was isolated previously from a Kenyan soda lake, Lake Magadi. Most cells of strain Ah-36(T) occurred in irregular clusters, and the colonies were orange-red, The polar lipids of this organism were composed of C-20, C-20, and C-20, C-25 derivatives of phosphatidylglycerol and phosphatidylglycerophosphate. Phosphatidylglycero-(cyclo-) phosphate, which is characteristic of Natronococcus occultus, was not detected. The complete nucleotide sequence of the 16S rRNA gene revealed that the closest relative of strain Ah-36(T) is N. occultus ATCC43101(T) (level of similarity, 96.4%), an extremely halophilic archaeon, However, strain Ah-36(T) did not exhibit a significant level of DNA homology to N. occultus ATCC43101(T), which represents the only previously described species in the genus Natronococcus, We describe a new species for strain Ah-36(T), for which we propose the name Natronococcus amylolyticus.