To ensure good conditions for growth and heteropolysaccharide production by the red microalga Rhodella reticulata, optimization of the medium and conditions was performed. Stimulation of the growth of microalgal cells up to1.6-fold was achieved with a new medium. Maximal growth rate (µ=0.19 d-1) was reached at the beginning of stationary phase of growth (72 h), together with the increase in the pigment content. The influence of the great quantity of humic acids and thiamin in the medium (proved

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... by HPLC) on algal growth was also established. The amount of extracellular polysaccharide (0.365 mg ml-1) produced by the algal cells cultivated in the new medium was 1.4-fold higher compared to the quantity in the standard medium. The immobilization of Rhodella reticulata cells into super-macroporous cryogel of 2-hydroxyethylcellulose lead to a prolonged period of storage. Algal cells were vital after three months and could be successfully used for the production of extracellular polysaccharide with values for immobilized cells 1.3-fold higher than those for free cells.