Flocculation of <i>Micractinium reisseri</i> for successful harvesting and potential use

This study includes <i>Micractinium reisseri</i> cultivation in artificial saline medium (ASM). With the aim of harvesting the bulk <i>M. reisseri</i> biomass, an experiment was set up at a bench scale to evaluate the best flocculation technique with the least compromising biomass and lipid loss. The flocculation efficiencies for the <i>M. reisseri</i> biomass have been studied using the auto-, bio-, and chemical-flocculation methods. Different concentrations of chitosan for the biological method and alum for the chemical method were added in <i>M. reisseri</i> culture growing in the liquid ASM. The optimal concentration with the highest biomass and oil collection was determined for each method. In the biological method, the highest (96.44%) and lowest (67.88%) flocculation efficiencies were observed by adding 15 and 2 mg of chitosan, respectively, and in the chemical method, the highest (97.2%) and lowest (35.4%) flocculation efficiencies were observed by adding 150 and 50 mg of alum, respectively. The auto-flocculation method shows the highest efficiency (97.8%) among all the tests. The oil yield from the three highest biomasses was 2.60, 1.51, and 1.08% in the auto-, bio-, and chemical-flocculation methods, respectively. The time taken for auto-, bio-, and chemical-flocculation was 48, 4, and 1 h, respectively.