Establishment of axenic cultures of Anabaena flos-aquae and Aphanothece nidulans (Cyanobacteria) by lysozyme treatment

A new method using lysozyme for the production of axenic cultures of Anabae na flos-aquae De Breibisson and Aphanothece nidulans P, Richter was develop ed. Cyanobacterial growth was not inhibited at concentrations up to 1.2 g.L -1 of lysozyme, whereas the growth of heterotrophic bacteria was suppressed , At concentrations up to 0.8 g.L-1 of lysozyme, ampicillin caused a reduct ion of heterotrophic bacteria. The axenic cultures of these strains were ac quired through a simple treatment using 1.0 g.L-1 of lysozyme without ampic illin. These cyanobacteria resisted digestion by lysozyme at our experiment al concentrations, whereas bacteria were digested selectively. This method of purification seems to be especially useful with cyanobacterial species t hat are sensitive to antibiotics or other germicidal agents.