초록
<P>The microalga <I>Haematococcus pluvialis</I> is capable of accumulating natural astaxanthin when subjected to external stress and shifted towards a red-cyst phase, characterized by a robust and multilayered cell wall. In the present study, still-unexplored solvents were applied for extracting astaxanthin from <I>H. pluvialis</I>, directly from algae culture and without any pre-treatment of the cells. Among the tested solvents, some of them (<I>e.g.</I> ethyl acetate and 2-methyltehydrofuran) gave excellent astaxanthin recovery (>80%) in a short time (30 min) and others (<I>e.g.</I> isoamyl acetate, well known as a human-compatible solvent and already in use as a food additive) gave an astaxanthin recovery close to 90% in 1 hour and thus they are exploitable in the natural astaxanthin market. Almond oil is proved to be able to extract astaxanthin and keep <I>H. pluvialis</I> alive, without affecting the algal photosynthetic activity, providing the possibility to milk and regeneratively cultivate <I>H. pluvialis</I> and avoid an uneconomical loss of biomass.</P><P>Graphic Abstract</P><P>Natural astaxanthin can be recovered from <I>Haematococcus pluvialis</I> culture without any cell pre-treatment by using human-compatible solvents, and can be re-synthesized by cells if algae-compatible solvents are applied in a milking mode, avoiding a net biomass loss.<BR/><IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c9gc01273g'/><BR/></P>