Growth and metabolism of Chlorella vulgaris under the influence of manganese and iron

Abstract

The aim of this study was to investigate the effect of manganese(II) and iron (III) on the growth and basic metabolic processes of the unicellular alga Chlorella vulgaris. To this end, alga cultures were treated with ions of iron(III) and manganese(II) at concentrations 0.1, 0.5, 2, 5, 10, 20 and 50 mg L-1 and then analyzed in terms of changes in the number of cells, content of monosaccharides, proteins, chlorophyll and the activity of antioxidant enzymes: superoxide dismutase and glutathione reductase. The development of C. vulgaris was influenced more by manganese(II) than iron(III). The largest increase in the number of cells and concentrations of the studied biochemical parameters and antioxidant enzyme activity was induced by 20 mg L-1 manganese(II). The experiment also showed that an appropriate amount of iron (III) helped control the level of manganese(II) thanks to the co-precipitation of metals, and so could help in tackling the worldwide problem of eutrophication. In the case of introduction of 50 mg L-1 of both iron(III) and manganese(II), the number of C. vulgaris cells decreased, and thus the concentration of the biochemical parameters in water. The results of these experimental studies well collaborate with a study conducted earlier of surface water, which showed the existence of a strong correlation between the concentration of manganese in the water and algal biomass, whose determinant is chlorophyll a.