ABSTRACT
Haematococcus pluvialis Flotow (hereafter referred to as “Haematococcus”) is a biflagellate, unicellular, green alga with spherical, ellipsoidal, or pear-shaped cells. The cup-shaped chloroplasts bear multiple pyrenoids. The protoplast is connected to the outer cell wall by numerous strands of cytoplasm that extend through the gelatinous surrounding wall material (Elliot 1934; Santo and Mesquita 1984). Studies of Haematococcus go back over a century’s history with Flotow’s early observations on this alga in 1844. The first extensive description of the life history of Haematococcus in English was by Hazen (Hazen 1899). The ability of this alga to accumulate high levels of astaxanthin has long been recognized 268(Goodwin and Jamikorn 1954; Boussiba 2000). At the time Hazen (1899) described the life history of Haematococcus, the chemical nature of this red coloring matter within the alga was unknown but was given the name “haematochrom.” Astaxanthin is present in lipid globules outside the chloroplast of Haematococcus. Its functions in the cell are complex, at least including protection from photodamage by reducing the amount of light impacting the light-harvesting pigment–protein complex (Boussiba and Vonshak 1991; Yong and Lee 1991). Astaxanthin has broad applications in the aquaculture and poultry industries as a feed additive to improve the coloration of cultured fish and crustaceans, and of egg yolks, and is also a potent bioactive antioxidant with applications in the cosmetic, nutraceutical, and pharmaceutical industries (Benemann 1992; Hussein et al. 2006). The price for 5% natural Haematococcus astaxanthin in oil currently sells in bulk for about USD 800 per kg, while synthetic astaxanthin (mainly used in aquaculture) sells for almost 10-fold less, based on market sources (J. Benemann, 2014, pers. comm.).
