A thermophilic Bacillus isolated from an Eolian shallow hydrothermal vent,able to produce exopolysaccharides

A thermophilic aerobic microorganism, able to produce two exocellular polys accharides (EPS1 and EPS2), was isolated from a shallow hydrothermal vent a t Vulcano island (Eolian Islands, Italy). EPS1 and EPS2 were based on manno se and glucose although in a different ratio. EPS2 possessed a trisaccharid e repeating unit with a manno-pyranoside configuration. New isolate phenoty pe was studied by physiological and morphological observations, including b iochemical and antimicrobial susceptibility tests (134). Previous analyses carried out on 87 field isolates and 8 thermophilic reference bacilli displ ayed low phenotypic similarity level (S-SM = 65%) with Bacillus thermodenit rificans DSM 465. Optimal growth occurs at 65 degreesC and pH 7.0. Oxidase and catalase are negative. The guanine-plus-cycosine (G+C) content of DNA i s 52.7%. Genotypic investigations demonstrated the diversity of the isolate with fifteen selected thermophilic Bacillus spp. when we compared the rest riction patterns of the amplified 16S rDNA. The membrane lipids are based o n fatty acids mainly belonging to the iso-family.