6.2.2. Green Solvent-Mediated Extraction

An environment-friendly downstream process using common vegetable oils was proposed by Kang *et al*. [79] for direct extraction of astaxanthin from *Haematococcus* sp. As said crude microalgal astaxanthin consists of *ca*. 70% monoesters, 25% diesters and 5% free forms, a rather lipophilic nature results, so vigorous stirring is required to gradually disrupt the cells; the oily extracts are then simply separated from the culture medium containing cell debris by gravity settling. When using olive oil, recoveries of up to 93.9% were possible [79]. Apparently, a similar method had been  proposed long before by Nonomura [80], who then claimed up to 7.5% yield of lutein. 
