Screening of High Exopolysaccharide Yield Strain of Boletus edulis by UV Ray

To enhance the exopolysaccharide production by Boletus edulis,the strain was mutagenized by using UV-irradiation was performed,and the conditions for it s protoplast preparation and regeneration of the mycelium incubation time,enzyme concentration,enzyme temperature,enzyme time,and osmotic stabilizer were examined.The result s showed that the mycelia incubated for 56 h were most suitable for protoplast release.The mixture solution of 1% fiber enzyme/1% snail enzyme and(0.010 92) g/mL mannitol was the most effective osmotic stabilizer and was most favorable for protoplast preparation.The suitable incubation temperature and time for the release of protoplast was 30~35 ℃ and 2 h.With the optimum conditions,the protoplasts and the regeneration rate was 3.71×10~5 and 7.32%,respectively.Compared with that of parent strain,the yield of exopolysaccharide production by mutant strains increase 30.4%.