Studies on protoplast formation and regeneration ofGanoderma lucidum

To obtain a new strain ofGanoderma lucidum by protoplast fusion technique, its protoplast formation and regeneration were studied. Several factors affecting the protoplast formation and regeneration were investigated to find their optimum conditions. The mycelium was grown for four days on the cellophane membrane placed onG. lucidum complete medium (GCM). When various commercial lytic enzymes were examined for protoplast isolation, the combination of Novozym 234 and β-glucuronidase was found to be effective. An osmotic stabilizer, 0.6 M sucrose in 20 mM phosphate buffer pH 5.8, gave the highest yield of protoplasts. Three-hour incubation in shaking incubator was most suitable for releasing protoplasts. To increase the protoplast yield, pretreatment with 2-mercaptoethanol was carried out. The regeneration frequency in GCM containing 0.6 M MgSO₄·7H₂O was shown to be 0.66%.