Production of the antibiotic cyanobacterin LU-1 by Nostoc linckia CALU 892 (cyanobacterium)

Cyanobacterin LU-1, produced by Nostoc linckia CALU 892, inhibits the growth of many cyanobacteria and eukaryotic algae. The minimum effective dose of a crude preparation to Synechococcus sp. R-2 is ca 1 µg ml^?1. The antibiotic hinders cell division and light-dependent oxygen evolution in Synechococcus sp. R-2 (PCC 7942) cells. It is not active against heterotrophic bacteria and fungi, and is non-toxic to mice. Purified cyanobacterin LU-1 contains a nitrous heterocycle with sugar and phenolic substituents. Cyanobacterin LU-1 accumulates in the medium during the course of growth, although not in direct proportion to cell density. Productivity of the culture depends on temperature.