Screening Of High-yield Polysaccharide Athelia Rolfsii And Fermentation Technology Optimization

The polysaccharide produced by Sclerotium has a lot of excellent characteristics, such asthickening, pseudo-plastic, antibacterial, anti-tumor activeness and immune activity. As aresult, the polysaccharide can be applied in the area of food, pharmacy, ceramic andpetroleum. The polysaccharide will be used more widely once the problem of cost andproductivity is solved. In this study, a strain of Sclerotium was Screened which was cultivatedto produce polysaccharide. At last, a mutant strain could use Corn starch and Maize yellowpulp as carbon source and nitrogen source respectively was obtained to producepolysaccharide heavily by optimizing the condition of cultivation and culture medium andscreening the strain by UV Mutagenesis, NTG mutagenesis and UV-NTG generationmutagenesis.1A strain of fungus was identified as Athelia rolfsii (Sx1) based on morphologicalobservation and18S rDNA sequence analysis.2The optimal fermentation conditions obtained by response surface methodology wereas follows: temperature29℃, pH4.55, noculated quantity7%, rotation speed200r/min and5.5d fermentation period. The amount of crude polysaccharide in the fermentation conditionswas14.458g/L.3Using the optimal fermentation conditions, the optimal fermentation mediumobtained by response surface methodology were as follows: starch35g/L, corn soaksolution50mL/L, NaNO33.1g/L, KH2PO41.0g/L, KCl0.5g/L, MgSO4·7H2O0.25g/Land citric acid1.4g/L.The amount of polysaccharide in the optimal fermentation conditionsand fermentation broth was16.135g/L.4Using UV mutagenesis condition: radiation time50s, diluted Athelia rolfsii liquidgradient10-3, incubation time in seed culture medium24h. Screening for UV7under thiscondition, the polysaccharide production from UV7was17.759g/L.5Using NTG mutagenesis condition: NTG concentration0.4mg/mL, NTG treated time40min. Screening for NTG7under this condition, the polysaccharide production from NTG7was18.573g/L.6Using NTG combined with UV mutagenesis condition: UV radiation time40s,NTGconcentration0.28mg/mL, NTG treated time25min. Screening for X2under this condition,the polysaccharide production from X2was19.868g/L.