Breeding Erythorbic Acid Yield Strains by Protoplast Mutagenesis

The results of experiment showed that the optimum condition for preparation of protoplast to Penicillium griseofulvum HL as the starting strain was incubation time of mycelium of 48h,osmotic stabilizer of 0.7 mol/L sodium chloride,enzyme combination of 0.5% snailase +0.5% cellulase,hydrolysis temperature of 30℃ and enzymolysis time of 3h with pH value of 6.0.Under this condition the yield of protoplast could reach 3.14×107/ml.The optmium condition for regeneration of protoplast of Penicillium griseofulvum HL was improved examine's medium as the regeneration medium with osmotic stabilizer of 0.7 mol/L sucrose and regeneration method of double-layer solid culture.Under this condition the regeneration rate of the protoplast was 24.93%.The protoplasts of Penicillium griseofulvum HL were induced by ultraviolet ray,diethyl sulfate,ultraviolet ray and diethyl sulfate,ultraviolet ray and LiCl,a high-yield strain of erythorbic acid ZD4 was obtained by first screening of flat plate and second screening of shake flask.The yield of erythorbic acid was increased from the initial 1.23mg/ml to 5.28mg/ml.And it can descend stably after six generation.