One-step cultivation of green algae <i>Haematococcus pluvialis</i> Flotow (Chlamydomonadales) for astaxanthin production
The laboratory technique of one-step semi-continuous cultivation of green microalgae <i>Haematococcus pluvialis</i> Flotow as astaxanthin (AST) source has been proposed. The method is based on the induction of AST biosynthesis in vegetative cells using sharp negative gradient of biogenic elements content in the medium at light irradiance of 120 µmol·m <sup>-2</sup>·s <sup>-1</sup>. Maximum AST daily output (1,85 mg ·l <sup>-1</sup> ·day <sup>-1</sup>) and AST content in biomass (1,8 - 2,6 % dw) have been obtained under 20 % daily culture dilution and nitrogen and phosphorus input of 0,2 and 0,01 mM ·l <sup>-1</sup>·day <sup>-1</sup>, accordingly. This cultivation mode provides a significant increase of AST bioavailability due to stable predominance of monad cells in cultures (85 - 97 %).