Caracterisation biochimique de l'algue verte Scenedesmus abundans: Influence des conditions de culture

Abstract

To evaluate aspects of enhancement of the green algae Scenedesmus abundans (Chlorophyceae), its biochemical composition was examined in cultures exposed to different environmental conditions. Amongst the factors studied, temperature has the greatest effect. Protein content is maximal at 15°C, while lipid and carbohydrate contents were maximal at 25°C and 35°C respectively. Light intensity has no effect on protein and carbohydrate content, but the lipid component decreases by approximately 20% at a light intensity of 300 μmol quanta.m-2.s-1. Moreover the nitrogen source has no significant effect on the cellular content of these three compounds. An increase in nitrogen concentration induces an increase in protein and lipid content with, however, a reduction in biomass production above concentrations of 400 mg l-1 KNO3. Modifications of the biochemical composition of Scenedesmus abundans as a function of the growth phase have also been observed. In the stationary growth phase, these modifications can be summarised as a marked reduction in protein content and, to a lesser extent, in lipid content, accompanied by a considerable accumulation of carbohydrates. The results are analysed taking into account the production yield of each of the three types of compound.