Large-scale Production Of Haematococcus Pluvialis And Selection Of Astaxanthin-producing Strain

Astaxanthin (3,3’-dihydroxy-β,β--carotene-4,4’-dione), an extremely high antioxidant activity is approximately10times greater than13-carotene, and over100-550times greater than vitamin E. Due to its high antioxidant properties, astaxanthin has high application potential in pharmaceutical, health products, cosmetics, food and feed industries. H. pluvialis is found to be the most suitable biological source among the astaxanthin producing organisms, because of its ability to accumulate astaxanthin up to4%(w/w) of dry weight. It is crucial problem to achieve rapid cell growth and high astaxanthin accumulation by means of regulating its life cycle and finding the finest strains. Liu Jianguo reported the intricate life cycle can be simply divided into motile cell stages and non-motile cell stage, that the cell proliferated chiefly by asexual propagation with2,4or8zoospore formed. The cell continuously release autofignals and feedback the cell growth along with the increase of cell concentration and the lengthening of incubation time. In order to find the most suitable strains in each month, we surveied and evaluated several growth indeices such as cell number, cell size, OD value, chlorophyll content and astaxanthin content. We also added sodium acetate, a kind of organic carbon, as well as phytohormone in culture medium with the purpose of promoting cell growth and astaxanthin accumulation. The result shown that Ho is suitable in1,2,3,4,5,6,9and11month, while the appropriate strains in8and12month is H2,moreover, H3is fitting in7and10month. The culture medium added with sodium acetate0.8g/L is optimum for the cell growth higher2.47times than control group, however, the effect of sodium acetate0.6g/L is not very obvious. Sodium acetate0.6g/L can furthest increase the astaxanthin content, as high as1.52times compared with1.23times for sodium acetate0.8g/L.We can sum up that the increase of astaxanthin content is mainly by the raising of intra-cellular astaxanthin accumulation. When we added auxin (NAA,3-IBA)and cytokinin(6-BA,kt) in culture medium, the effect of different strains is distinct. Overall, however, the phytohormone can promote the cell growth and astaxanthin accumulation, while, there are no obvious influence to cell size. According to laboratory result and phytohormone market price, we are recommending that NAA1.75mg/L and3-IBA4mg/L can be used in mass production to perfect the culture of Haematococcus pluvialis.