The act ion of Zn(II) acetate on adaptive capacity of spirulina in response to chan ges in the light regime

Abstract

The presence of chemical stimulators may be a factor leading to the loss of adaptive capacity of cyanobacterium to changing cultivation conditions with accumulation of oxidative degradation products of lipids. In order to monitor the adaptive capacity of spirulina, grown in the presence of zinc acetate as stimulator of protein synthesis, cyanobacterium has been subjected to light-induced oxidative stress. During the adaptation period, Spirulina platensis was grown in the presence of 15 mg/l of Zn(II) acetate under optimal conditions with continuous illumination. On day 3 of cultivation cycle, corresponding to early exponential growth phase, spirulina was exposed to stress by reducing light period up to 4 hours from 24 hours. Thus, lighting regime was with photoperiodism of 4 hours light/20 hours dark. This regime was followed until day 7 of cultivation. It was used as control sample spirulina, grown in the absence and presence of zinc acetate under optimal conditions. In spirulina biomass, collected every 24 hours, was determined the content of malondialdehyde (TBARS assay).