DARK ANAEROBIC METABOLISM OF HALOPHILIC CYANOBACTERIUM MICROCOLEUS CHTONOPLASTES

We investigated dark anaerobic metabolism of Microcoleus chtonoplastes , an ubiquitous microorganism in water ecosystems with moderate and ex treme salinity. In the absence of light and oxygen, the microorganism was capable of fermenting carbohydrates accumulated during light expos ure, forming acetate as the main product, and of anaerobic respiration using elementary sulfur as an electron acceptor and forming hydrogen sulfide. The only function of these physiological mechanisms apparentl y is survival of the organism, since no culture growth was observed un der dark anaerobic conditions.