The flat panel airlift-photobioreactor of Subitec.


The cultivation technology of Subitec is based on a uniquely designed inexpensive plate reactor. The FPA-reactor prevents disadvantages based on their design of conventional photobioreactors. The systematic technology advantage leads to a range of benefits. Hereby, the patented stream guidance induced by static mixers depicts the key for the success of the FPA-reactor.


  • Optimal light distribution to all cells by stream guidance induced by static mixers.
  • Complete intermixing and homogenization avoids photo-oxidative stress and improves efficiency of cultivation, especially at high light intensity.
  • Photoinhibition constrains photosynthesis in other systems.
  • Minimal shear-stress on algae.
  • Simple control of temperature and pH, efficient gas transfer.
  • Higher cell densities compared to other systems. 
  • Reduction of aeration rate (turbulence) at low light intensities.
  • Pulse-aeration during nighttime to prevent cell sedimentation.
  • Integration of solar arrays as plant's ideal energy source – times of energy production and demand match.
  • Flexible scalability of production capacities due to modular construction.

Light distribution is decisive.

The cross-section of each photobioreactors can be intersected into three zones of diverging light intensity. Directly at the surface light intensity is so high that photosynthesis can hardly take place (photoinhibition). This section is followed by a thin division of optimal light intensity. In the deepest zone, self-shading of the culture leads to light limitation. The FPA-reactor operates by following the principle of an airlift-loop-reactor and achieves an optimal light supply of all microalgal cells through the small layer thickness and the stream guidance induced by static mixers. The solution is the directed transport of cells enforced by the incorporation of the like. Rising gas bubbles are refracted and they transfer the culture medium into a stationary, circular flow. Herewith, all microalgal cells are transported from the illuminated reactor surface area and thereof away in an interval of about 1 Hertz. By varying the distance between FPA-reactors during outdoor cultivations average light intensity on the reactors may be altered.

Even light input into Subitec's FPA-reactor.

Large reactor surface with controlled light guidance.

Construction in two transparent plastic half-shells.