Abstract: The present invention relates to a method for cultivation and manufacturing efficiently algae containing useful substances in cells thereof in a high concentration. According to conventional cultivation apparatus, shear stress applied to algae causes difficulty of high density cultivation; however, by cultivation of algae by using a convenient cultivation apparatus having a dome shape, conical shape, or cylindrical shape and made by a clear material, high density cultivation has been realized without shear stress. The present cultivation apparatus realizes more efficient cultivation in combined use with a separate gas discharging apparatus. In addition, the present invention can be applied to a wide variety of algal species having ability to produce highly unsaturated fatty acid, a photosynthetic pigment, or a polysaccharide.

Abstract: This invention relates to a culture device of a domed shape, a conical shape, or a cylindrical shape of a closed type used for culture of microalgae, and a gas discharge device set so as to be movable in the culture device. The culture device is basically composed of a transparent inside member (a semispherical dome, a conical peripheral wall, or a cylindrical peripheral wall), a transparent outside member, and a bottom portion connecting the lower ends of the two members, a cylindrical opening portion is provided at the top part of the outside member, and a gas introducing member and a discharging member of a culture solution are provided in the bottom portion. The gas discharge device is basically composed of two opposed rectangular base plates, a bubble guide member, and a discharge nozzle. The culture solution can be agitated without mechanical agitation and the culture can be carried out in high concentrations.