ISOLATION AND CHARACTERIZATION OF 3 THERMOPHILIC ANAEROBES FROM A ST-LUCIA HOT-SPRING

Three thermophilic anaerobes were isolated from a sample of mud taken from a hot spring located in St. Lucia. A rod - shaped, autotrophic, thermophilic methanogen was isolated. This St. Lucia Methanogen (SLM) closely resembled Methanobacterium thermoautotrophicum, type strain delta H, but demonstrated a sufficient number of unique features to warrant its designation as a new strain. The remaining isolates were peritrichously flagellated, spore-forming eubacteria. The fermentative, saccharolytic St. Lucia Hexagonal array organism (SLH) displayed an optimal growth temperature of 60-65-degrees-C, and a DNA base composition of 30.2 mol% G + C. The proteinaceous surface layer (S-layer) of this isolate featured hexagonal (p6) symmetry and was composed of a glycoprotein of Mr = 200,000. The SLH organism appears to represent a new thermophilic member of the genus Clostridium. The St. Lucia Tetragonal array organism (SLT) was an autotrophic sulfate-reducer with a temperature optimum for growth of 60-65-degrees-C and a DNA base composition of 51.4 mol% G + C. This isolate possessed an S-layer of tetragonal (p4) symmetry and a component protein of Mr = 83,000. The SLT organism appears to be a new thermophilic member of the genus Desulfotomaculum.