Study On Purification And Rejuvenation Of Protoplast Of Pleurotus Nebrodensis And Optimization Of Liquid Fermentation Conditions

There are some problems in the cultivation of Pleurotus nebrodensis,such as long production cycle,low bioconversion rate and teratogenesis.Liquid fermentation technology can not only shorten the production cycle of edible fungi,but also can shorten the fermentation time in the course of cultivation.In this study,two varieties of Pleurotus nebrodensis “Zhongnong winged abalone” and“baiza 65”,were used to breed new strains of Pleurotus nebrodensis with high yield and low rate of deformity Response Surface Methodology(RSM)was used to optimize the liquid fermentation conditions of Pleurotus nebrodensis strain “Baiza 65”,the end point of liquid culture of Pleurotus nebrodensis was determined by sensory observation,microscopic examination,germination activity,reducing sugar content in fermentation broth and laccase activity:1.The results of protoplast purification and rejuvenation breeding of “Zhongnong wing abalone”showed that 15 better protoplast strains were screened out from 52 protoplast strains by clamp connection identification,mycelium length and speed comparison,and low temperature stimulation.In the cultivation experiment of 15 protoplast strains and the control group,the time for 4 strains to grow full fungus bag was 15 days earlier than that of the control group,and the time for 11 strains to grow mushroom was 8 ? 13 days earlier than that of the control group.Five strains were not easy to produce malformed mushroom,and the biological conversion rate of four strains was 100% ? 120%.The fresh weight of PN1-10 strain was 598.04 g per single mushroom,and the biological conversion rate was close to 120%.2.The liquid fermentation of Baiza 65 was optimized by single factor test and response surface methodology(RSM)with mycelium biomass as the response value,the three factors of carbon,nitrogen source and inoculation quantity were optimized.The results showed that the mycelium biomass reached the maximum of 2.145 g when the glucose was 24.590 g/L,the yeast extract was7.433 g/L and the inoculation amount was 10.929%.3.Based on the optimum combination of liquid fermentation conditions,this thesis studied the liquid strain “Baiza 65” of Pleurotus nebrodensis through sensory observation,microscopic examination,germination activity,reducing sugar content in fermentation broth and laccase activity.The results showed that when the fermentation culture reached the 5th day,the mycelia grew rapidly with moderate mycelial density,the strongest laccase activity,and the mycelia had more clamp connection combination during the fermentation period.The rejoining plate germinated quickly.The p H value of the fermentation broth began to decrease with the increase of mycelia amount.The reducing sugar content in the fermentation broth decreased sharply,and the soluble protein content increased.