Study On Optimization And Application Of Liquid Strain Fermentation Technology Of Pleurotus Geesteranus

Pleurotus geesteranus is a new edible fungi.Due to its delicious taste,rich nutrients and important health care effects,it has been loved by people in recent years.The market demand of P.geesteranus is increasing year by year,and the supply is in short supply.However,the current production mode of P.geesteranus is mainly solid strain cultivation technology,which is not conducive to improving the production of P.geesteranus and the development of its deep processed products.In recent years,people have used the liquid fermentation technology to carry out the preparation and application of liquid strains of edible fungi such as Flammulina velutipes,Lentinus edodes and Pleurotus eryngii,but there are relatively few studies on P.geesteranus,Therefore,on the basis of previous studies,this paper optimized the fermentation medium and fermentation conditions of oyster mushroom liquid strain fermentation technology;And then,We detected and analyzed the relevant indicators of the fermentation process and established the fermentation kinetics model.Finally,a bag planting experiment was carried out on the cultivar of P.geesteranus.The main research results are as follows:1.Study on fermentation medium of liquid mushroom strain of P.geesteranus.Using the inexpensive and widely sourced materials and mycelium biomass as the index,the optimum carbon source,nitrogen source and its addition range,and the optimal addition range of the two inorganic salts were selected by single factor test.Then,the formula of liquid fermentation medium of P.geesteranus was further optimized by orthogonal test design.The results showed that the optimal culture medium compoment was:11%rice flour,1.2%soybean powder,0.30%KH₂PO₄,0.12%MgSO₄·7H₂O,and 0.01%VB₁.Under this formula,the biomass of mycelium obtained by liquid strain fermentation of P.geesteranus reached 4.65±0.03 g/100 mL.2.Optimization of fermentation conditions of liquid mushroom species of P.geesteranus.On the basis of the optimal medium,we carried out single factor experiments on the basic fermentation conditions,then screened the fermentation conditions by Plackett-Burman experiments and climbing experiments.Finally,response surface test was used to optimize the factors with significant influence.According to the actual production conditions,we modified the optimized fermentation conditions,the final fermentation conditions were:liquid loading 18%,inoculum 10%,speed 150 r/min,initial pH 5.5,temperature 25°C.Under this fermentation conditions,the biomass of mycelium obtained by liquid strain fermentation of P.geesteranus reached 5.93±0.10 g/100mL after fermentation for 7 days,which was 26.7%higher than the biomass obtained only by optimizing the fermentation medium.3.Fermentation kinetics research.According to the optimal fermentation process mentioned above,through the detection of mycelial biomass,starch content,extracellular polysaccharide content and pH of the fermentation process of the liquid strain of P.geesteranus,the optimal fermentation cycle obtained by our analysis was 7d,the maximum mycelium biomass was 5.92±0.20 g/100mL,and the extracellular polysaccharide was 1.710.06 mg/mL.The results show that the trend of change between the indicators has a certain regularity,and the metabolic process is a coupled type of growth.The kinetic models of mycelial growth,extracellular polysaccharide synthesis and substrate consumption were established by linear transformation method based on Logistic equation and luedeking-piret equation.The average error between the calculated and experimental values of the three models was less than 10%,indicating that the model fits well.4.Contrast cultivation experiment between liquid and solid strains.The liquid and solid strains of P.geesteranus were prepared and inoculated into the same solid culture base material namely cultivation bag,and then bagged under the same conditions.The results showed that the production cycle of the liquid strain cultivation group was significantly shorter than that of solid strain cultivation group.In the period of preparation,liquid strains needed 19 days and the solid strain needed 37days.During the growth stage of the bacteria bag,the liquid strains group needed 30 days to fill the bag,while the solid strains group needed 45 days.At the same time,the fruiting was relatively orderly in the liquid strain group,and there was no significant difference in fruit body shape,yield and solid strains.It showed that the liquid strains obtained under this research process had greater production advantages than the solid strains.