An efficient method for the sequential production of lipid and carotenoids from the Chlorella Growth Factor-extracted biomass of Chlorella vulgaris

Efficient methodology for simultaneous extraction of multiple bioactive compounds from microalgae still remains a major challenge. The present study provides a method for the sequential production of three major products: Chlorella Growth Factor (CGF, a nucleotide-peptide complex enriched with vitamins, minerals, and carbohydrates), lipid, and carotenoids from Chlorella vulgaris biomass in an economically feasible manner. After protein-rich CGF was extracted, the spent biomass was found to contain 12% lipid and 3% carotenoids when extracted individually, compared to that of the un-utilized (fresh) biomass (lipid, 14%; carotenoids, 4%). When extracted simultaneously using conventional methods, the yield of lipid from CGF and carotenoids-extracted biomass, and carotenoids from CGF and lipid-extracted biomass were significantly reduced (50%). However, simultaneous extraction using different solvent mixtures such as hexane:methanol:water and pentane:methanol:water mixture-augmented lipid yield by 38.5% and carotenoids by 14%, and additionally retained chlorophyll and its derivatives. Column chromatographic approach yielded sequential production of lipid (18%), lutein (9%) with better yields as well as without chlorophyll interference. Different geometric isomers of lutein all-E-(trans)-(3R,3'R,6'R)-beta,epsilon-carotene-3,3'diol, 9Z(cis)-(3R,3'R,6'R)-beta,epsilon-carotene-3,3'diol, and 13Z(cis)-(3R,3'R,6'R)-beta,epsilon-carotene-3,3'diol were purified by HPLC and elucidated by CD, UV, NMR, FT-IR, and Mass spectra. In conclusion, the study provides an efficient and economically viable methodology for sequential production of lipid and lutein along with its geometrical isomers without chlorophyll influence and yield loss from the protein-rich CGF-extracted spent biomass of marine microalga, Chlorella vulgaris.