PROMOTIVE EFFECT OF 5-AMINOLEVULINIC ACID ON THE GROWTH AND PHOTOSYNTHESIS OF SPIRULINA-PLATENSIS

Photosynthetic activity in terms of Oz evolution and the growth of Spi rulina platensis was stimulated by adding 5-aminolevulinic acid (ALA, 500 mg/l) to photoautotrophically growing cells. After ALA was added t o the medium, intracellular accumulations of phycocyanin and chlorophy ll were stimulated simultaneously, followed by enhancement of the phot osynthetic activities of photosystems I and II, and lastly, growth was promoted. ALA did not directly activate the photosynthetic electron t ransport system. However, during a 3-h incubation of intact cells with ALA, photosynthetic activity was enhanced.