Separation, Purification, and Identification of (3S,3′S)-trans-Astaxanthin from Haematococcus pluvialis

Abstract

A simple, low-cost method of separation and purification for preparing (3S,3′S)-trans-astaxanthin from Haematococcus pluvialis was established in this study. Crude extracts were separated from dry algal cells by extraction. The extracts were then saponified at 4°C for 15 h and at 22°C for 3 h with 0.02 M NaOH in the reaction mixture with lower isomerization of trans-astaxanthin to cis isomers. The saponified pigment extracts were mixed with distilled water and n-hexane at 1:1:1 volume ratio. Low-pressure column chromatography of silica gel (300-400 mesh) with different eluents was used to prepare high-purity (> 80%) all-trans-astaxanthin. Supersaturated solution of astaxanthin in acetone was then crystallized for 72 h at 4°C, and the purity of all-trans-astaxanthin crystalline powder was confirmed to be > 96.5% by HPLC. And the 3S,3′S isomers were identified and characterized by HPLC-APCI-MS, ¹H NMR, ¹³C NMR, and HPLC-UV.

Keywords:

• (3S,3′S)-trans-astaxanthin
• Haematococcus pluvialis
• separation
• purification
• identification