The main ingredients in the cell walls of most flowering plants include cellulose–xyloglucan framework, pectic polysaccharides and structural proteins (Carpita and Gibeaut, 1993). The pore diameters of the cell walls of plants have average pore diameter of 38–40 Å. The molecular size of lutein is estimated by ChemOffice at 27–28 Å; therefore, it can pass through cell wall pores without difficulty. However, most lutein in microalgae is bound with proteins and other such pigments as LHCs. Hence, lutein in microalgae is more difficult to extract without cell disruption than that in marigold flowers.