The effects of immobilization on physiology and ultrastructure of unicellular alga Platymonas subcordiformis

In the present paper, the unicellular green alga Platymonas subcordiformis was entrapped in 2% (W/V) alginate, treated with CaCl₂ at different concentrations (0.5, 0.75, 1.0, 1.5 and 2.0 mol/dm³), cultured at 15℃ and 25℃.The growth rate and morphology were studied and photosynthesis and respiration rates were measured.The optimum conditions of immobilized culture is in 0.5 mol/dm³ of CaCl₂, at 25℃.Photosynthesis rate of immobilized cells is higher than free cultivated cells, and that at 15℃ than at 25℃.Under scanning electropic microscope, it was shown that the immobilized cells had larger size and rougher surface.The relationship between growth of immobilized cells and abiotic factors and the prospects of applying immobilized cultivation are also discussed.