Production and regeneration of protoplasts from <Emphasis Type="Italic">Grateloupia turuturu</Emphasis> Yamada (Rhodophyta)

Protoplasts were isolated enzymatically from the carrageenophyte red alga Grateloupia turuturu (Halymeniales, Rhodophyta) that occurs along the coast of the French Channel in Normandy. Effects of the main factors on the protoplast yield were identified to improve the isolation protocol. The optimal enzyme composition for cell wall digestion and protoplast viability consisted of 2% cellulase Onozuka R-10, 0.5% macerozyme R-10, 2% crude extract from viscera of Haliotis tuberculata, 0.8 M mannitol, 20 mM sodium citrate, 0.3% bovine serum albumin at 25°C, and 4-h incubation period. The protoplasts were approximately 5–15 μm in diameter, liberated mainly from the surface cell layers. Maximum yield was 1.5 × 10⁷ protoplasts g^-1 fresh tissue. The protoplasts underwent initial division after 14 days with a high density level of 1 × 10⁶ cells mL^-1 in culture medium and developed into microthalli of a line of two to six cells.