Lysis of cyanobacteria with Flexibacter spp isolated from domestic sewage.

Five species of filamentous cyanobacteria and two species of Flexibacter were isolated from domestic sewage. Cells and filtrates of F. flexilis and F. sancti lysed the cyanobacterium Oscillatoria williamsii. Inhibition of the photosynthetic electron transport reactions, and glycolate dehydrogenase and nitrogenase activity of O. williamsii due to its incubation with F. flexilis, were observed. Scanning electron micrographs revealed the attachment of F. flexilis to the sheaths of O. williamsii which resulted in the excretion of lysozyme and lysis of the cyanobacterium. Seasonal variations of Flexibacter spp showed that they were more abundant in the aeration tanks during June compared with sewage effluents.