8^th Euro Biotechnology Congress

Biography

Biography: Hela Ben Amor-Ben Ayed

Abstract

A study investigating the accumulation of magnesium by Chlorella vulgaris under different culture conditions is described. The dissolved and biomass-associated concentrations of magnesium were measured with atomic absorption spectroscopy during the course of C. vulgaris growth under autotrophic or mixotrophic conditions both in shake-flask (100 mL) and photo-bioreactor (5 L) cultures. The adsorbed (extracellular) and absorbed (intracellular) ions associated with the biomass were determined using adapted published methods. During the experiments, a clear relationship between the growth extent of C. vulgaris and magnesium removal from the medium was observed. In an autotrophic shake-flask culture with a medium concentration of 19.1 mg Mg2+/L), 78% of the initial magnesium content of the medium was associated with the biomass of which 6% was adsorbed on the cell wall and 72% absorbed into cells at the end of the experiment (480 hours). In a mixotrophic photo-bioreactor culture with glucose (10%) as the sole organic carbon source, C. vulgaris accumulate 90% of the initial magnesium content of the growth medium of which 4% was adsorbed on the cell wall and 86% absorbed by the biomass. Magnesium association with C. vulgaris was faster and more extensive under mixotrophic conditions. These results could be interesting for the accumulation of metal ions by microalgae on an industrial scale.