Flocculation of Micractinium reisseri for successful harvesting and potential use

This study includes Micractinium reisseri cultivation in artificial saline medium (ASM). With the aim of harvesting the bulk M. reisseri 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 M. reisseri 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 M. reisseri 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.