Table 2.

Differences between synthetic and natural astaxanthin.

	Synthetic Astaxanthin	Natural Astaxanthin	Reference
Stereochemistry	(3R,3′R), (3R,3′S), (3S,3′S) optical isomers-1:2:1	(3R,3′R), (3R,3′S), (3S,3′S) optical isomers-1:2:22	[40]
Structure	Non-esterified	More than 95% of the natural astaxanthin molecules are esterified	[40,41]
Industrial uses	Aquaculture feed	Food and dietary supplements, cosmetics, nutraceuticals, aquaculture feed	[41,42]
Market Price	USD 2000 per kg	USD 7000 per kg	[43]
Production	-Wittig reaction of two C15-phosphonium salts with a C10-dialdehyde -Hydroxylation of canthaxanthin. -C10 + C20 + C10 synthesis via dienolether condensation. -Isomerization of a lutein extracted from marigold to zeaxanthin, and then oxidation to astaxanthin.	-- Extraction from algae -- Extraction from yeasts	[44]
Production Price *	800–900 €·kg−1	1000–7000 €·kg−1	[43]

* Production costs vary significantly between different locations from a theoretical 600–700 €·kg⁻¹ in China [13] to 6000–7000 €·kg⁻¹ in the Netherlands [11].