Screening Of Cordyceps Militaris CM-1 Strain And Fermentation Process Of Mycelium

Cordyceps militaris is a valuable edible and medicinal fungi with high value for medicine and economy purposes.In recent years,The artificial culture of Cordyceps militaris has already realized industrialization.But the quality and effect of the product are not uniform and stable.In the strategic background of "healthy China",more and more enterprises are concerned about the improvement of cordycepin content.Cordycepin is the main active ingredient in Cordyceps militaris.Therefore,it is urgent to conduct a systematic and in-depth research of artificial culture.The high yield and stable Cordyceps militaris strains were screened through this experiment.The mycelium dry weight and cordycepin content increased and the genetic stability was stable of the strain.In this experiment,the strain of cordyceps was isolated from the wild Cordyceps militaris,and the strains of cordyceps were isolated by plate separation technology,and the high yield strains were screened and obtained by measuring the body weight and dry weight of the different strains,the dry weight of mycelium and the content of cordyceps.How each nutrient factors and physical conditions affects the content of cordycepin in culture medium was studied by single factor test method,orthogonal test design and response surface method during the culture of Cordyceps militaris.The reactor was used to amplify the laboratory optimization results and further optimize the industrial production conditions.The conclusions are as follows:1.Isolated 16 strains Cordyceps militaris in this experiment,through the experiment of antagonism prove to 16 different species,identification.cultivate cycle sporocarp dry weight,fruit body morphology as indicators for early screening,mycelium growth rate,mycelium dry weight andcolony size as an index to last screen,results names CM-1.As the target strain for production,it has been proved to be a stable Cordyceps militaris by molecular identification and genetic stability of mycelia in 20 successive generations.CM-1 strains were cultured by fruiting bodies and mycelia respectively.The results showed that mycelium culture was not affected by strain generation.So It is suitable for industrial production.2.Base on CM-1 strains studies carbon source,nitrogen source nutrition condition,types and dosage of inorganic salt nutrition by single factor and orthogonal experimental method.Experimental results show that the CM-1,the optimal level of Cordyceps militaris strains fermentation combination 3 g of peptone,20 g of glucose,2 g of 7 water magnesium sulfate,1.5g of potassium dihydrogen phosphate;Compared with the optimization of the medium,the mycelial biomass of CM-1 was 19.44 g per liter and the yield increased by 33%.The content of cordyceps is 56.82 mg per liter,which is 20.76 mg per liter higher than before.3.CM-1 as the starting strain,investigate different temperature,quantity,inoculated fungus age,medium initial pH,culture period,temperature,table speed cultivating environment factors influence of Cordyceps militaris mycelium growth and development,provide a reference for mycelium after applied to industrial production data.Experimental results show that the Cordyceps militaris CM-1 liquid culture the training cycle for 4 days,the optimal pH value of6.5,cultivate temperature of 26 ?,inoculation amount 9 %,with fluid volume is 450 m L(when the culture vessel for a 1000 m L conical flask),rotating speed of 110 r·min-1,the mycelial biomass of CM-1 was 28.66 g per liter and the content of cordyceps is 56.26 mg per litere.4.On the basis of above results,artificial culture of Cordyceps militaris was further studied in 20 L reactor,the suitable conditions were: The ventilation volume is 1: 0.8 V·(V·min)-1,the tank pressure is 0.06 MPa and the defoaming agent content is 0.15 %.For the sake of safety and non-toxic side effects,the raw material level of the medium is changed to food grade.The detection result of mycelium biomass and cordycepin content showed the yield of mycelium of CM-1 strain is not reduced and the cost is reduced after replacing the raw material level.The price of Cordyceps militaris mycelium produced with food grade raw materials is 0.013 yuan per gram,which costs less 0.057 yuan per gram than the Cordyceps militaris mycelium produced with analytical grade raw materials.5.The growth and metabolism curves of Cordyceps militaris were drawn on the optimized experimental conditions.It shows that the fermentation process can be divided into two stages,one is the growth stage mainly based on the growth of bacteria,the other is the product generation stage based on the metabolites.This means that the best process parameters must be determined in stages to ensure the maximum growth rate of the mycelium at the growing stage,while the bacteria can provide the most significant metabolites at the production stage of the product.