DESCRIPTION OF BACILLUS-THERMOAEROPHILUS SP-NOV, TO INCLUDE SUGAR-BEET ISOLATES AND BACILLUS-BREVIS ATCC 12990

Isolates of thermophilic bacteria obtained from an Austrian beet sugar factory were screened by sodium dodecyl sulfate-polyacrylamide gel el ectrophoresis (SDS-PAGE) and freeze-fracture electron microscopy for t he presence of glycosylated crystalline cell surface layers (S-layers) , On the basis of similarities in the protein band patterns on SDS-PAG E gels and the lattice geometry of the S-layers as revealed by electro n micrographs, the 31 isolates which we studied were clustered into fi ve groups (groups I to V) and several strains which exhibited no commo n characteristics (group 0). We found that the organisms belonging to groups I to III had glycosylated S-layer proteins, but the highest car bohydrate contents were observed in group III organisms, Partial seque ncing of the 16S ribosomal DNAs of selected representative strains of each group revealed that the group I, II, IV, and V isolates and the f ew group 0 strains were different from the group III strains, The resu lts of DNA-DNA hybridization experiments, SDS-PAGE, and an analysis of polar lipids demonstrated that group III isolates L419-91, L420-91(T) (T = type strain), and L438-91 belong to the same species, We chose t he group III organism Bacillus sp, strain L420-91(T) for further analy sis because of the high carbohydrate content of its S-layer protein, T he taxonomic position of this isolate was determined by using a polyph asic approach, Phenotypic, chemotaxonomic, and genomic analyses reveal ed that strains L420-91(T), L419-91, and L438-91 represent a new Bacil lus species, We observed high levels of similarity between these strai ns and Bacillus brevis ATCC 12990, which also had a glycosylated S-lay er protein. Our results show that strains L420-91(T), L419-91, and L43 8-91 and B. brevis ATCC 12990 belong to the same species and that this species is a new Bacillus species, which we name Bacillus thermoaerop hilus. The type strain of this species is strain L420-91 (= DSM 10154) .