Recovery of lutein from microalgae biomass: development of a process for Scenedesmus almeriensis biomass.

In this work an optimized method for the extraction of lutein from microalgae biomass is presented. It has been developed using dry biomass of the lutein-rich microalga Scenedesmus almeriensis. The method comprises three steps, cell disruption, alkaline treatment, and solvent extraction, and renders a carotenoid extract rich in lutein. The results demonstrate that cell disruption is necessary and that the best option among the treatments tested with regard to industrial applications is the use of a bead mill with alumina in a 1:1 w/w proportion as disintegrating agent for 5 min. With regard to the alkaline treatment, the optimal conditions were obtained using 4% w/v KOH with a biomass concentration of 100 g/L for 5 min. Longer alkaline treatments or the use of higher KOH concentrations reduced the yield of the process. Finally, extraction with hexane is optimized. Using a 1:1 ratio hexane to sample volume, a total of eight extraction steps are necessary to recover 99% of lutein contained in the processed biomass. However, the optimal number of extraction steps is six, 95% of the lutein being recovered. In summary, the developed method allows the efficient recovery of lutein from microalgae biomass, it being a scaleable and industrially applicable method.