Selection And Application Of Excellent Fermented Pleurotus Citrinopileatus Strains By MPMS Mutagenesis

The edible mushroom industry has made great contributions to the overall victory in the battle against poverty.Many local governments have regarded the edible fungus industry as one of the important industries for development.In the next step to consolidate the achievements of poverty alleviation and complete the rural revitalization strategy,the edible mushroom industry still has an important position and will continue to play a role.Rare class of edible mushrooms as a sunrise industry still has great potential for development.However,due to the crisp texture and other reasons,the circulation of P.citrinopileatus is limited.At present,there are few fresh products of P.citrinopileatus on the market.With the intersection of modern fungus industry and fermentation industry,factory liquid fermentation has become one of the symbols of the progress of edible mushroom industry.It has become a modern production model for artificial utilization of edible mushroom that using liquid fermentation culture and the rich secondary metabolites in fermented mash to develop processing technology.In this study,in order to enrich and optimize the strains of P.citrinopileatus in Hebei Province,select and breed excellent strains of P.citrinopileatus,and improve the fermentation performance,MPMS was used for the first time to breed the original strains of the institute.The optimal mutagenesis time for MPMS of P.citrinopileatus was determined to be50 s,and a total of 308 mutant strains were obtained.Then,using the starting strain as a control,27 mutant strains with obvious antagonistic response to the starting strain were obtained by primary screening by antagonism.Through re-screening and comparing 4indicators of biomass,polysaccharide content,laccase activity and carboxymethyl cellulase activity,it was finally determined that the fermentation characters of the mutant strains YH67,YH103,YH122 and YH265 were better than the starting strains.Among them,YH122 has the best traits and is the most suitable mutagenic strain for liquid fermentation.the ISSR molecular marker technology was used to identify the authenticity of the four excellent strains YH67,YH103,YH122,YH265 and the starting strain finally obtained by mutagenesis and screening,to further determine the genetic differences between the mutagenized strain and the starting strain at the molecular level.The results showed that the genetic similarity coefficients between the four excellent mutagenic strains and the starting strains were in the range of 0.38-0.67.This indicates that there are different degrees of genetic differences at the molecular level between the four excellent mutagenic strains of P.citrinopileatus.Therefore,it can be determined that YH122 is an excellent fermentation strain obtained by MPMS mutation breeding of P.citrinopileatus.In this paper,the nutrient conditions of liquid fermentation of YH122 were optimized.The optimal fermentation medium formulation was obtained by optimizing the fermentation conditions of YH122 by response surface methodology,and the formulation was glucose3.40%,corn flour 0.70%,soybean meal 0.70%,yeast extract 0.60%,potassium dihydrogen phosphate 0.15%,magnesium sulfate 0.16%,vitamin B1 0.0013%.Under this formula,the fermentation biomass of YH122 can reach 46.64 g/100 ml,which is 18.80% higher than the original medium formula,and the total flavonoid content can reach 46.48 mg/L,which is13.25% higher than the original medium formula.Both were significantly better than the basal medium formula.Use this formula for YH122 liquid fermentation,the kinetic model of liquid fermentation of P.citrinopileatus was established,including the growth kinetic model of mycelium,the synthesis kinetic model of liquid fermentation products and the substrate consumption kinetic model of liquid fermentation of P.citrinopileatus.In this way,we can better grasp the dynamic balance of YH122 fermentation in optimized medium.According to the previous research of our institute,the application of thickeners has formed the rapid breeding technology achievements of Auricularia auricula liquid strains of the A.auricula industry innovation team in Hebei Province.On this basis,this paper explored the effects of different types and concentrations of thickeners on YH122 strain liquid fermentation,and finally determined the optimum thickener to be tamarind gum,and the addition amount was 0.15%.The time for this liquid strain to grow full in the grain medium is6 days,which is obviously better than that of the original strain.In this paper,the semi-dry fermented wine with YH122 strain fermented mash as main ingredient was obtained through improvement and optimization.The preparation process of the wine was obtained as follows: yeast inoculum 8%,sucrose addition 24%,temperature30℃,p H 3.5,fermentation time 96 h.The semi-dry fermented wine obtained by brewing according to this process is bright in color and mellow in flavor.The alcohol content of the wine is 11.2%vol,the total sugar content is 7.63 g/L,and the total acid(calculated as citric acid)is 3.78 g./L.The hygienic index of the wine conforms to the relevant national standards,and it provides new technical support for the development of the P.citrinopileatus processing industry.