The application of microalgae in bioremediation processes is studied to remove toxic components and ions excess that cause eutrophication.  Algae use the nutrients excess present in the water to produce biomass through photosynthesis. On the other way, microalgae are used in environmental monitoring, these organisms are sensitive to both natural and anthropogenic pollutants, which promote or inhibit cell and population growth. The present study aimed to determine an optimal matrix for the immobilization of Chlorella sp. It is a native species of the region. The matrices tested were 4 % calcium alginate and 4 % alginate-agar. For the culture, Bold's medium was used, and growth kinetics were carried out for each treatment in Bach-type culture, during 21 days of incubation. The response variables were maximum cell concentration, cell viability and conservation of the spheres. The maximum cell concentration was 1.07x10⁶ cells.mL and it was reached after 15 days of culture, in 4% alginate spheres. The doubling time was 0.162 and 0.141 for Chlorella sp. Retained in 4 % alginate matrix and 4 % alginate agar, respectively. Regarding the quality of the spheres, after 15 days of culture, the disintegration process of the Alginate-Agar immobilization system began. The alginate spheres remained unchanged for the 21 days of the experiment. In conclusion, the best treatment for the immobilization of Chlorella sp was obtained when 4 % alginate was used, and it is recommended to continue the studies for the development of the bioremediation system, biomass production and biosensors.