Extraction, purification and concentration of partially saturated canthaxanthin from Aspergillus carbonarius

A mutant Aspergillus carbonarius produces partially saturated canthaxanthin (PSC; C(40)H(62)O(2)) during submerged fermentation. The pigment was extracted from dried biomass using various organic solvents and purified using nanofiltration (NF) and nonporous membranes. Particle size had a great influence; PSC extractability from fines fraction of biomass (75-105 microm) was 1.5-fold higher compared to the coarse fraction (850-920 microm) in ethanol. Among the four solvents, hexane exhibited the highest PSC extractability of 5.83 mg/g and purity of 32 mg/g. On a relative scale, the extraction performance of hexane, acetone, methanol and ethanol were in the order 100, 16.1, 7.5 and 5.4. An assessment based on enrichment factor and permeate flux revealed notable performance with NF-250 membrane in ethanol extract followed by NF-200 and NF-GKSS membranes in methanol extract. These results suggested the suitability of hexane for extraction followed by alcohol phase purification and concentration employing NF. Accordingly, a PSC purity of 206 mg/g was achieved.