Abstract: According to the proposed method for producing biomass, the organisms or cells in a suspension kept in circulation in a photobioreactor are cultivated with introduction of light and of at least CO2 as a nutrient. For the cultivation, the suspension is introduced via at least one introduction organ in an upper region of a culturing space and its downward movement is slowed down by at least one inner element that has a horizontally extending grid, screen or net structure and that is disposed in the culturing space. The suspension is converted into a plurality of drops on this structure. The drops pass through a drop cycle, by means of which the downward movement of the suspension is slowed down and a particularly intensive exposure of the organisms or cells contained in the nutrient solution to nutrients and light introduced into the reactor is assured.

Abstract: A bioreactor for culturing microorganisms which has a reactor vessel, a plurality of gas-introduction tubes and a gas-introduction system for introducing gas into a culture medium in the gas-introduction tubes via injectors, wherein the gas-introduction tubes are connected by their respective lower end, in the vertical direction, to the reactor vessel and by their opposite upper end to the upper end of an upright vessel which is likewise connected by its lower end to the reactor vessel, and at the upper end of the upright vessel an expansion vessel is arranged.