Carotenoid and lipid production by the autotrophic microalga Chlorella protothecoides under nutritional, salinity, and luminosity stress conditions

Abstract

Today microalgae represent a viable alternative source for high-value products. The specie Chlorella protothecoides (Cp), heterotrophically grown, has been widely studied and provides a high amount of lutein and fatty acids (FA) and has a good profile for biodiesel production. This work studies carotenoid and FA production by autotrophic grown Cp. Cp was grown until the medium's nitrogen was depleted, then diluted in NaCl solution, resulting in nutritional, luminosity, and salinity stresses. Different NaCl concentrations were tested (10, 20, 30 g/L) at two different dilutions. After dilution, a color shifting from green to orange-red was noticed, showing carotenoid production. The best production of both carotenoids and FA was attained with a 20 g/L NaCl solution. The total carotenoid content was 0.8 % w/w (canthaxanthin (23.3 %), echinenone (14.7 %), free astaxanthin (7.1 %), and lutein/zeaxanthin (4.1 %)). Furthermore, the total lipid content reached 43.4 % w/w, with a FA composition of C18:1 (33.64 %), C16:0 (23.30 %), C18:2 (11.53 %), and less than 12 % of C18:3, which is needed to fulfill the biodiesel quality specifications (EN 14214).

Astaxanthin and Related Xanthophylls

“…This is the case for Chlorococcum humicola [ 56 ] and Coccomyxa acidophila (which also accumulate signifi cant amounts of β-carotene) [ 57 ], C. zofi ngiensis (which also accumulates astaxanthin) [ 58 ], and Dunaliella salina [ 59 ] and Chlorella protothecoides (which also contain signifi cant amounts of canthaxanthin, echinenone, and astaxanthin) [ 60 ].…”

Alterations of the lipid content and fatty acid profile of Chlorella protothecoides under different light intensities

“…protothecoides in environmental stresses including: nutritional stress, salinity and luminosity in autotrophic growth (Campenni` et al, 2013), nitrogen limitation in heterotrophic and mixotrophic cultures (Wang et al, 2013).…”

Optimizing biodiesel production in marine Chlamydomonassp. JSC4 through metabolic profiling and an innovative salinity-gradient strategy

“…These species include Chlorella sorokiniana [12], Nannochloropsis sp. F&M-M24 [13], Nannochloropsis gaditana [10], D. tertiolecta ATCC30929 [14], and C. protothecoides [15]. …”