Electron microscopic observations of Chlamydomonas reinhardtii cells immobilized in agar bends revealed that many colonies are assembled over the gel surface and are enlarged during growth. When the microalga reached the stationary phase of growth, the chlorophyll content in the gel beads remained constant, but the gel surface showed microinterstices that allow cell release to the culture medium. The viability was maintained by the cells; thus, this system could be interesting in applied processes operating continuously.