Studies On Parameters Control Of Submerged Fermentation, Extraction And Carboxymethylation Of Pachyman

Poria cocos is a valuable medicinal and edible fungus, which always be used in traditional Chinese medicine. Pachyman can improve immune functions, prevent and treat cancer, and other new functions are constantly found and recognized. At present, pachyman is mainly producted from the wild or cultivated, which limits its applications. In this paper, the liquid fermentation was used and polysaccharide isolated from fermentation broth was gained.This process has advantages such as short cycle, low cost, et al. To sum up, polysaccharide and other bioactive compounds are more and more needing Liquid fermentation technology and new separation and extraction technologies, which is the new direction of industrial production.In this paper, Povia cocos HD 08-10 was studied. Mycelia of the strain HD 08-10 were cultured by submerged fermentation and the optimum fermentation parameters were obtained. Isolation of polysaccharides from mycelia was studied and get the optimum parameters. Pachymaran was chemically modified by carboxymethylation and optimal reaction conditions were searched. CMP was identified through multi-step purification, component analysis, chemical analysis and physical characterization. There is a great significance to expand the scope of application.A single-factor experiment was designed to select the optimal ratio of carbon sources and nitrogen sources, temperature, shaking speed, pH, inoculum size and other parameters were studied. An orthogonal experimental design was used to optimize the fermentation parameters. The optimal parameters were as follows: glucose 4 %, peptone 0.75 %, KNO3 1.5 %, MgSO4·7H2O 0.05 %, KH2PO4 0.1 %, pH 5.5 , temperature 26℃, shaking speed 150r/m, liquid volume 80 mL, inoculum 6 %.Single factor experiment and response surface methodology were applied to optimize the extraction parameters of polysaccharides. a three-level Box-Behnken factorial design was employed combining with response surface methodology to optimize the extraction parameters. A maximal yield of polysaccharide (2.45 %) could be obtained when the time, temperature and ratio of water to material were set at 4.3 h, 73.8℃and 29.8:1, and the yield could be up to 2.57 % in validation experiments. The extraction parameters obtained by the response surface methodology was credible and had feasibility and application value.Optimization of the preparation conditions of CMP was studied and the optimal conditions were as follows: temperature 50℃, NaOH 1 %, chloroacetic acids 7g. Identification of CMP was studied through multi-step purification, component analysis, chemical analysis and physical characterization. The results indicated that CMP was composed of carboxymethyl glucose. CMP wasβ-type glucosan and connected mainly via aβ(1→3) glycosidic bond. CMP was glucopyranose and its molecular weight was about 4.2×104 Da. The viscosity characteristics of CMP were studied. The results indicated that the viscosity changed with concentration, temperature, pH and other factors.