Aqueous enzymatic process for cell wall degradation and lipid extraction from Nannochloropsis sp.

An effective cell disruption method, including alkaline pretreatment and subsequent enzymatic treatment, was established to break cell walls and extract lipid from Nannochloropsis sp. A synergistic effect was found between alkaline pretreatment and enzymatic treatment. The combination of commercialize enzymes (cellulase, protease, lysozyme, and pectinase) achieved higher lipid yield compared with a single enzyme application. With the compromise between economic feasibility and lipid yield, the optimum reaction conditions were obtained with alkaline pretreatment at pH 10.5 at 110 °C for 4 h, and subsequent enzymatic treatment at pH 4 at 50 °C for 30 min with the dosage of each enzyme at 200 IU/g. As high as 90.0% of lipid was extracted under optimal conditions from Nannochloropsis sp.