Abstract: The invention provides a bioreactor for culturing living cells, particularly shear sensitive cells, wherein the bioreactor is composed of a stationary vessel with opposite spaced walls inclined at an angle to form upper and lower walls. Liquid culture medium and cell culture, such as hybridoma cells, are introduced into the vessel and gas is introduced at the lower end of the vessel to form gas bubbles which travel upward along the upper wall of the bioreactor to disengage from a small portion of the gas liquid interface. The gas bubbles circulate the cells and liquid medium, maintaining the cells in suspension and lifting them in a circulating path upwardly parallel to the upper wall and downward along the lower wall. The bioreactor design thus achieves bulk mixing and aeration by maintaining a significant degree of segregation between the upwardly travelling bubbles and the cells in the liquid medium avoiding unnecessary cell damage by fluid-mechanical shear or by bubble bursting events.