Research On Co-fermentation Of Fungal Polysaccharides By Sanghuangporus Lonicericola And Cordyceps Militaris

In this paper,the main goal of co-fermentation of fungal polysaccharides with Sanghuangporus lonicericola and Cordyceps militaris is as follows,The co-fermentation method,co-fermentation medium and fermentation conditions were studied,and the polysaccharide extraction from the mycelium obtained by co-fermentation was tested.On this basis,the main active ingredient content and the antioxidant activity difference of polysaccharide of the single bacteria and co-fermented mycelium were compared.The main findings are as follows:1.A co-fermentation model for producing polysaccharides was established by Sanghuangporus lonicericola and Cordyceps militaris were fermented for 3d and 1d respectively before combined fermentation.The key medium components affecting the yield of co-fermentation fungi polysaccharides of two bacteria were determined by single factor experiment,which were divided into soluble starch(A),beef extract powder(B),K2HPO4(C)and MgSO4·7H2O(D).Based on the Box-Behnken experimental design principle and response surface analysis method,the key components of the fermentation medium of co-fermentation fungi polysaccharides of Lonicera edulis and Cordyceps militaris were optimized,and the prediction model of co-fermentation fungal polysaccharides was obtained:Y1=480.52+78.64A+12.69B13.08C-23.95D-2.51AB+9.41AC-5.93AD+1.75BC+6.82BD+13.26CD-85.72A2-154.27B2-129.03C2-110.55D2.The optimal medium composition was predicted to be:soluble starch 32.20g/L,beef extract powder 12.07g/L,K2HPO4 1.11g/L,MgSO47H2O 0.36g/L.Validation tests on the validity of the model showed that the measured values of the total polysaccharide yield were very close to the predicted values,indicating that the model was effective.2.Based on the optimization of the co-fermentation medium,the key factors affecting the fermentation conditions of the co-fermentation fungal polysaccharides of Lonicera edulis and Cordyceps militaris were determined by single factor test and Plackett-Burman test design:inoculum volume(A),culture temperature(B),initial pH(C).Based on the Box-Behnken experimental design principle and response surface analysis method,the key fermentation conditions affecting the cofermentation of fungal polysaccharides of Sanghuangporus lonicericola and Cordyceps militaris were further optimized,and the fungal polysaccharide fermentation of co-fermentation of Lonicera edulis and Cordyceps militaris was predicted.Conditional regression model:Y2=1045.87-45.98A+126.66B+50.42C+62.52AB-8.68AC-26.17BC-213.76A2-119.93B2-305.91C2.Further analysis of the parameters,the best fermentation conditions for co-fermentation of fungal polysaccharides were:inoculum volume 19.86%,culture temperature 30.05℃,initial pH=7.06.In order to facilitate the actual operation experiment,the parameters were corrected to inoculum volume 20%,culture temperature 30℃ initial pH=7.The verification test was carried out according to the modified fermentation conditions,and the actual measured value was 1071.47±9.32 mg/L,which was basically consistent with the predicted value of 1080.64 mg/L,and the model was effective.3.The polysaccharide extraction from the mycelium obtained by co-fermentation of Sanghuangporus lonicericola and Cordyceps militaris was studied.The results showed that the extraction efficiency of ultrasonic extraction method was the highest.The best extraction process was as follows:the ratio of material to water was 1:50(g/mL);the ultrasonic power was 320W;the ultrasonic time was 50min.The effects of Sevage method,trichloroacetic acid method,HCl method and CaCl2 method on the deproteinization of polysaccharides were compared.The CaCl2 method was used for deproteinization.When the calcium chloride content was 5%,the polysaccharide yield was 93.66.%,the deproteinization rate was 90.7%.The macrochromic resin HD-3 was used for decolorization.4.The contents of polysaccharides,triterpenoids and flavonoids in the mycelium obtained by single bacteria and co-fermentation were compared.The results showed that the content of polysaccharides,triterpenoids and flavonoids in the mycelium obtained by co-fermentation was significantly higher than that of single bacteria.The antioxidant activities of the mycelium polysaccharides obtained by single bacteria and co-fermentation were compared,and the DPPH free radical scavenging rate,hydroxyl radical scavenging rate and superoxide radical scavenging rate were determined.The results showed that the three free radical scavenging rates of co-fermented mycelium polysaccharides were about 65%,which was significantly higher than that of single-species polysaccharides,indicating that the co-fermented mycelium polysaccharides had good antioxidant activity and it has certain development and utilization value.The elution of three mycelium polysaccharides by DEAE-cellulose column chromate-graphy was compared,it is preliminarily proved that the polysaccharide obtained by co-fermentation bacteria differs from the component of the polysaccharide obtained by fermentation of a single bacteria.