Resumo

MORALES, Ever et al. Crecimiento, producción de pigmentos y exopolisacáridos de la cianobacteria anabaena sp. pcc 7120 en función del ph y co2. INCI [online]. 2002, vol.27, n.7, pp.373-378. ISSN 0378-1844.

Growth, production of chlorophyll a, phycocyanin, carotenoids and exopolysaccharides (EPS) of the filamentous cyanobacterium Anabaena sp. PCC 7120 were analyzed as a function of pH (5.5-10.5) with or without buffers in batch cultures and as a function of CO2 (0.03 and 5%) in semicontinuous cultures with a renewal rate of 10%. The growth of the cyanobacterium was analyzed by turbidity at 750nm and cell count, and the photosynthetic activity by means of an O2 electrode. All cultures were maintained, in triplicate, with constant aeration at 28±2°C and continuous light or photoperiod, according to the experiment. Growth was influenced by the pH and buffer used. The highest growth rate and EPS content were reached at pH 8.0-9.0 and 10.0, respectively. However, non buffered cultures had higher contents of chlorophyll a and phycocyanin. Growth, photosynthetic activity and carotenoids did not vary with the addition of CO2. Semicontinous cultures with low CO2 yielded the highest values of chlorophyll a, phycocyanin and exopolysaccharides, with 25.9±1.69, 2010±22.61 and 2286.0±42.76 µg·ml-1, respectively. Phycocyanin and EPS content was 2.7 and 4 times higher than those obtained at high CO2 levels. The pH and semicontinuous system constitute important tools to modulate the growth and pigment and EPS contents of Anabaena sp. PCC 7120.

Palavras-chave : Anabaena ; Carotenoides ; Cianobacteria ; Clorofila ; Exopolisacárido ; Ficocianina ; pH .