Inorganic and Organic Compounds of Freshwater Filamentous Cyanobacteria under Normal and Salt Stress Conditions

The main aim of this work was to investigate the effects of salt stress conditions on the inorganic and organic compounds of extracts from six filamentous cyanobacteria： Arthospira platensis, Oscillatoria sp., Oscillatoria salina, Tolypothrix sp., Oscillatoria sp. SWU （Srinakharinwirot University）121 and Tolypothrix sp. SWU213. All cyanobacteria were cultures in BG （blue-green algae）11 medium： pH 7.5 at 35 ℃ for 30 days of sodium chloride in the culture medium presented 0-1.0 M. The cyanobacteria isolates grew well in BGH medium, nevertheless, growth of the majority of isolates was reduced by about 50% in the same medium containing 0.5 M NaCl. The inorganic compounds such as, Na^＋, K^＋, Ca^2＋, Mg^2＋, NH4^＋ and NO3^- were determined. All ions were reduced when NaCI was increased and Na^＋ showed highest amount in the medium followed with Mg^2＋, NH4^＋, NO3^- and Ca^2＋ in all cyanobaeteria. The organic compounds such as, betaine, proline and total lipid were determined under normal and salt stress conditions. We found that all cyanobacteria increased interesting organic compound under salt stress condition at least two folds to compare with normal condition. This is the first finding indicated that freshwater filamentous cyanobacteria could grow under salt stresses by accumulation of some organic compounds as osmoprotectants such as betaine and amino acids, being the reduction related to the amount of inorganies compounds present in cultures.