For efficient mass production of microalgae, we invented a novel photobioreactor that uses aeration for mixing. To select better chamber shapes for a photobioreactor, two aspects of its performance were numerically simulated, mixing and light reception. Two shapes survived the computational filters and were tested by cultivating Chlorococum littorale. One of them attained 20.5 g/m(2)/day in dry weight in the winter days in Japan. Recently, this figure was overwritten by the performance of 37.3 g/m(2)/day for Chaetoceros calcitrans with the maximum cell density of 2.5 g/L. (c) 2005 Elsevier Ltd. All rights reserved.