THERMUS-SILVANUS SP-NOV AND THERMUS-CHLIAROPHILUS SP-NOV, 2 NEW SPECIES-RELATED TO THERMUS-RUBER BUT WITH LOWER GROWTH TEMPERATURES

Strains of Thermus silvanus sp, nov, and strains of Thermus chliarophi lus sp, nov. were isolated from the hot spring at Vizela in northern P ortugal and the hot spring at Alcafache in central Portugal, respectiv ely, The strains of T. silvanus produce orange-red-pigmented colonies and have an optimum growth temperature of about 55 degrees C, while th e strains of T. chliarophilus produce yellow-pigmented colonies and ha ve an optimum growth temperature of about 50 degrees C. The strains of both species are catalase negative, These species can be distinguishe d from each other and from Thermus ruber by biochemical characteristic s, fatty acid composition data, and 16S rRNA gene sequence data, Our p hylogenetic analysis showed that strains VI-R2(T) (T = type strain) an d ALT-8(T) belong to the T, ruber line of descent, The type strain of T, silvanus is strain VI-R2 (= DSM 9946), and the type strain of T. ch liarophilus is strain ALT-8 (= DMS 9957).