GROWTH AND ASTAXANTHIN FORMATION OF HAEMATOCOCCUS-PLUVIALIS IN HETEROTROPHIC AND MIXOTROPHIC CONDITIONS

A green alga, Haematococcus pluvialis was able to grow heterotrophically on acetate in the dark as well as mixotrophically on acetate in the light. The photosynthetic pigments chlorophyll and astaxanthin were formed even in the dark-heterotrophic growth condition. The specific growth rate of the mixotrophic condition (acetate + light) corresponded well to the sum of the specific growth rates of the heterotrophic (acetate + dark) and autotrophic (no acetate + light) conditions. The results suggested that in H. pluvialis, unlike in most green algae, both photosynthesis and the oxidative metabolism of acetate can function in a concomitant manner for mixotrophic growth on acetate. The inhibition of photosynthesis with the addition of dichlorophenyl-dimethyl-urea (DCMU) also supported the two independent metabolisms under the mixotrophic growth condition.