Characterization of filament forming Bacillus strains isolated from bulking sludge

Several filament-forming Bacillus strains which have been isolated from bulking sludge have been examined by staining and microscopy. Two types of morphology were identified: a white, circular, mucous, non-rhizoid type with a rather smooth margin; a cream-coloured, rough, rhizoid type, with root-like filaments. Filaments extended to 100-150 um in length and had no sheath. The two types were physiologically similar, lipolytic on Tween 80, haemolytic on human blood, produced catalase, decomposed some proteins and had a positive egg yolk reaction. The DNA base compositions and GC ratios corresponded to the values published, which helped identify the bacteria as Bacillus cereus and Bacillus mycoides.