TAXONOMIC COMPARISON OF DIFFERENT THERMOPHILIC SUGAR-BEET ISOLATES WITH GLYCOSYLATED SURFACE-LAYER (S-LAYER) PROTEINS AND THEIR AFFILIATIONTO BACILLUS-SMITHII

During the beet sugar campaign 1991/1992 we have characterized thermop hilic bacteria from the extraction plant of an Austrian beet sugar fac tory in a polyphasic approach. Sodium dodecyl sulfate-polyacrylamide g el electrophoresis (SDS-PAGE) and freeze-fracture electron microscopy revealed the presence of weakly glycosylated, oblique crystalline cell surface layers (S-layers) on all sugar factory isolates. By partial 1 6S rDNA sequencing and DNA-DNA hybridisation it was demonstrated that the strains belong to the species Bacillus smithii. In the course of t he campaign, however, different strains of B. smithii became dominant, which was demonstrated by fingerprinting using SDS-PAGE, polar lipid analysis, random amplified polymorphic DNA (RAPD) assays, fluorophore- assisted carbohydrate electrophoresis (FACE). Possible explanations fo r this divergence in strain development are discussed from the technol ogical point of view.