Abstract: Orthogonal experiments were designed to study the optimized conditions for protoplast formation of Aspergillus ficuum .A 1% mixed solution of enzymes (0.5% cellulase + 0.25% snail enzyme + 0.25% lysozyme) was used to treat the body cells of A.ficuum, and the yield of protoplast was up to 3.2 × 10⁷ individuals·ml^-1 .The optimum osmotic stabilizer was 0.6 mol·L^-1 KCl containing 0.2 mol·L^-1 PO₄³⁺ (pH5.8), and the optimum duration and optimum temperature for enzymatic action was 3.0h and 30℃, respectively.The optimal conditions for protoplast regeneration were also obtatined, and the regeneration rate was over 30%.

Key words: Aspergillus ficuum, Protoplast formation and regeneration