Effect of flocculation on lipid extraction from Chlorella vulgaris Utex 1803 using response surface methodology

Microalgae are an attractive source of metabolites, such as lipids, proteins, pigments and carbohydrates, of potential interest to the pharmaceutical, food and energy sectors. The aim of this study was to evaluate the effect of flocculation on lipid extraction from Chlorella Vulgaris. A 3 3 experimental design was performed with STATISTICA 7.0 software in order to determine the effects of flocculant (AlCl 3 ) addition, pH and time. The best strategy of pH adjustment-flocculant addition was evaluated, followed by lipid extraction under optimal conditions. pH adjustment after the addition of flocculant provided higher flocculation efficiencies (87.2-98.9%) compared to adjustments made before adding the flocculant (67.8-85.9%). Experiments performed according to the experimental design led to a flocculation efficiency of 99.7% when 100 mg/L of AlCl 3 , pH 7 and a cultivation time of 18.3 days were used. The percentage of a lipid extract from the flocculated biomass was 2.7% and the flocculant did not affect the production of fatty acid methyl esters.