Study of low cost of microalgae chlorella sp. harvesting using cationic starch flocculation technique for biodiesel production

Abstract

Abstract The crisis of energy has become the main concern for human civilization. Microalgae is an attractive source of biomass for energy production because it has high productivity, does not compete with food, do not require a large area and its ability to absorb CO2. Chlorella sp. has the potential to be used as raw material for biodiesel due an oil content of 28-32% and easily developed in Indonesia. Harvesting is a very cost-determining step in converting algal biomass into biodiesel. Cationic starch has a strong potential as a flocculant agent because of its abundance and low price. This research aims to identify the potential of cation starch as a flocculant agent and obtain optimum the condition for harvesting Chlorella sp. Based on this study, cationic starch can be used as an alternative organic flocculant for Chlorella sp. The optimum dose and flocculation are 1 g/L dosage, 400 rpm flocculation speed and 15 minute flocculation time. With the optimum condition, harvesting efficiency on the laboratory scale is 98.23% and the pilot scale is 96.05%. This difference in harvesting efficiency values indicates that the efficiency tends to decrease with a larger volume of Chlorella sp.