Biotechnological investigation for the prevention of marine biofouling II. Blue-green algae as potential producers of biogenic agents for the growth inhibition of microfouling organisms

Biogenic agents were isolated from the benthic cyanobacteria Scytonema hofmanni and Calothrix brevissima by various extraction and purification (thin layer chromatography) (TLC) methods. These bioactive compounds were tested on the growth of a benthic diatom. Diatoms present the principal share of biomass of microfouling organisms. Nitzschia pusilla was chosen as the test organism. Extracts obtained from both cyanobacteria species cause strong growth inhibitory effects, Scytonema hofmanni producing the most effective antialgal compounds. The algicides from Scytonema hofmanni are synthesized and localized mainly in the cells, only traces are exuded into the culture filtrates. Antialgal compounds were not detected in culture filtrates of Calothrix brevissima.