Study On The Optimization Of The Fermentation Media Of The Highly-yielding Strain Cordyceps Militaris And The Anticancer Activity Of Its Polysaccharide

In this paper, the polysaccharide in highly-yielding mutagenic strain Cordyceps militaris N102 was studied. The chemometrics methods were applied to optimize the fermentation media. The yields of intracellular polysaccharide was used as the responsive values. Base on selecting the suitable carbon sources and nitrogen sources, the significant components in fermentation media were screened by PB design. Box-behken design was used for further optimization. Optimum fermentation media were obtained which were as follow (g/L): sucrose 17.23, peptone 13.80, MgSO₄·7H₂O 2.54. Three validation experiments with the optimum fermentation media were implemented and their average was 0.6251 g/L。The relative error was 1.07 %.Response Surface Methodology (RSM) was applied to optimize the extraction conditions of polysaccharide in Cordyceps militaris N102 mycelium. Extracting temperature, extracting time and the solvent/solid ratio were selected as causal factors. The yield of adenosine was used as the responsive values. Base on the single factors experiments, a three-factor-three-level experiments design have been developed by Box-Benhken central composite design method. The response surface method was employed to analyze the results of experiments. The results indicated that the optimum process conditions for the extraction conditions of adenosine were as follow: extracting temperature was 83.04℃, extracting time was 3.18 h and solvent/solid ratio was 51.93:1(mL/g). The predictive maximum yield of adenosine was 7.16 %. The average yield of adenosine in 3 validation experiments was 7.24 %. The relative error was 1.16 %. These results demonstrate that RSM analysis optimized the extraction conditions for polysaccharide in Cordyceps militaris N102 mycelium is feasible.Optimized the extraction conditions was used to extract polysaccharide of Cordyceps militaris N102. After repeated freeze-thaw, deproteinization, dialysis and ethanol precipitation, crude polysaccharide of Cordyceps militaris N102 ( 2FPS, 4FPS and 6FPS ) was obtained. The results of MTT assay showed that polysaccharides presented inhibitory activity on the cells proliferation of Hela. After 72h incubation, at the dose of 5.12 mg/mL, the inhibition rate of Hela were 74.98 % , and the IC₅₀ was only 1.72 mg/mL.