Distribution and identification of actinomycetes lysing cyanobacteria in aeutrophic lake

Among 83 actinomycete strains isolated from lake sediments, about half were found to lyse cyanobacteria. One (S-9 strain), identified as Streptomyces phaeofaciens, grew well on lawns of living cyanobacteria and rapidly lysed the cyanobacterial cells. The amino acid, L-lysine, secreted by this isolat e, was found to be one cause of lysis. Scanning electron microscopy of cyan obacterial cells incubated in the presence of L-lysine revealed that L-lysi ne caused severe damage to the cell wall.