ABSTRACT
This work aimed to study the influence of gamma radiation on the growth and production of some active substances of Arthrospira platensis. Biomass production was significantly inhibited (p ≤ 0.05) by 21 and 34%, with respect to the control at 2.0 and 2.5 kGy, respectively. Chlorophyll-a content showed 11% reduction at 2.5 kGy compared to the control. As a result of growth and Chl-a inhibition, chlorophyll productivity recorded a continuous significant decrease below the control in the cells exposed to 1, 1.5, 2 and 2.5 kGy by 8, 12, 15 and 25%, respectively after 15 days of incubation. In addition, phycobillins productivity showed significant decrease by 10 and 36% below the control at 2 and 2.5 kGy of gamma radiation, respectively. Protein production decreased significantly by 24% at 1.5 kGy; low doses of gamma irradiation (0.5, 1.0 and 1.5 kGy) induced carbohydrate production by 106, 246 and 146%, respectively. Lipid content increased significantly over the control at 0.5 kGy of gamma irradiation by 22%, which was decreased at higher doses. Interestingly, carotenoid productivity showed significant increase at all used gamma doses up to 155% over the control.