Abstract: The output , regeneration and mutagenesis of the protoplasts of Ganoderma. lucidum Karst No.1 that would produce high laccase activity were studied. The mutant G301 of enzyme activity as 2.83 fold higher than the original strain was obtained under 30W UV lamp, at a distance 40cm from the protoplasts, for 30s. The optimal conditions of protoplast output and regeneration are as follows: using 0.6mol/L sugar as osmotic stabilizer, the mycelium being incubated for 48 hours, the lytic enzyme solution containing a mixture of equal volume of 4%(W/V) Lywallzyme and 2%(W/V) snailase, pH6.0, and enzymatic time for 1 hour at 30℃.

Key words: laccase, Ganoderma lucidum Karst, protoplast, UV, mutant, breeding