SUSPENSION CULTURE AND FLOCCULATION OF CHLORELLA VULGARIS FOR IMMOBILISED CULTIVATION IN ANGLED BIOFILM PHOTOBIOREACTORS

Tóm tắt

Cultivation technology of Chlorella vulgaris shows great potential in wastewater treatment along with biomass collection for biofuel production. Suspended, autotrophic cultivation at various scales is still the main method to increase algal biomass in different stages of algae technology. In this study, C. vulgaris was cultured to proliferate in a 2 l suspension system to prepare biomass for immobilised cultivation in a biofilm photobioreactor. The initial cell density and light intensity suitable for suspension culture were determined to be 5.105 cells/ml and 120 μmol photons/m2/s. After 20 days of culture, the density of dry algal biomass in the 2 l system reached 0.315 g/l. To concentrate the algal suspension for immobilisation into biofilm, alum (KAl(SO4)2) was used at concentrations from 0.2 to 2 g/l to form flocculation. The concentration of alum 0.2 g/l was most efficient (95% of the algae in the suspension was flocculated), and the obtained algae had a strong proliferative ability when being immobilised in the angled biofilm photobioreactor.