A coiled transparent and flexible tube of small diameter with separate or attached degassing unit is the basis for the helical type of bioreactor. A centrifugal pump is used to drive the culture through a long tube to the degassing unit. CO2 gas mixture and feed can be circulated from either direction, but injection from the bottom gives better photosynthetic efficiency (Morita et al., 2001). A degasser facilitates removal of photosynthetically produced oxygen and residual gas of the injected gas stream. This system facilitates better CO2 transfer from gas phase to liquid phase due to a large CO2 absorbing pathway (Watanabe et al., 1995). The energy required by the centrifugal pump in recirculating the culture and associated shear stress limits this reactor’s commercial use (Briassoulis et al., 2010). Fouling on the inside of the reactor is another disadvantage of this system.