L’algue rouge <Gracilaria verrucosa> (Hudson) papenfuss de la lagune de Bizerte (Tunisie septentrionale) : essai de culture en mode suspendu et composition biochimique

Abstract

Gracilaria verrucosa, was grown using suspended modes at different depths and sites representing the biogeochemical differences of the Bizerte lagoon in the North of Tunisia during a spring 2009. The concentration and distribution of nutrients (ammonium, phosphate) in water, as well as the salinity, temperature and dissolved oxygen were determined. During this period some parameters as growth, concentrations of proteins, carbohydrates and pigments yield were investigated in order to evaluate the influence of the culture mode, site and depth on Gracilaria production. Internationally standardized analytical methods were applied in order to reach these objectives. Similar growth was observed in the lagoon. Gracilaria grew slower at a depths superior to 1.0 m. The major limiting factor of algae growth was found to be the light intensity. The results indicated that Gracilaria verrucosa showed a high range of protein (20%-30%), R-phycoerythrin contents (50-85mg/g weigh matter ) and a low content in carbohydrate (30%-35%).The proteins and R-phycoerythrin contents corroborate the potential use of the studied algae, which constitute useful raw material for the development of R-phycoerythrin extraction activity.