Solar Gum Soracan Gum Rheological Properties And Biological Activity

The preparation, rheology characteration and bioactivity of the Soracan gum from Myxobacterium NUST06 were investigated.On the base of factor experiments and L₉ (3⁴) orthogonal experiment, the optimum fementation conditions were showed that soluble starch 20 g/L, sucrose 10 g/L, NaNO₃ 2.5 g/L, CaCl₂ 0.05 g/L, MgSO₄ 0.15 g/L, KH₂PO₄ 1.0 g/L, FeCl₂ 0.1 g/L.Rheology of Soracan gum was measured, compared with Xanthan gum. Soracan gum thickened solution strongly, and exhibited excellent pseudoplastic behaviours. And Soracan gum exhibited better tolerance to salt. Apparent viscosity of 0.2% Soracan gum solution remained 93% and 92% respectively in 5%NaCl and 5%CaCl₂ solution, while 0.2% Xanthan gum solution remained 67%, 69% respectively. Soracan gum resisted acid and alkali better.In pH=2 or pH=13 solution, apparent viscosity of 0.2% Soracan gum solution remained 83%, 100% respectively, while 0.2% Xanthan gum solution remained 47%, 75% respectively.In addition, Soracan gum exhibited better tolerance to freezing-thawing. Apparent viscosity of 0.2% Soracan gum solution remained 100%, 91% respectively after freezing treatment or refrigeration treatment, while 0.2% Xanthan gum solution remained 94%, 75% respectively. And that apparent viscosity of 0.2% Soracan gum solution was affected by changes in temperature and heat-time to some extent, but still had good stability in the tested range. Besides, apparent viscosity of 0.2% Soracan gum solution increased rapidly with the increase of SDS (Sodium dodecyl sulfate) concentration. And when 0.5% SDS was added to Soracan gum solution, the viscosity was increased by 6.7 fold (2350 mpa·s). Apparent viscosity of compound system exhibited good tolerance to temperature, in 80℃solution, apparent viscosity of compound syetem remained 76%. What's more, it endured salt excellently. The results from the experiments showed that in 5%NaCl and 5%CaCl₂ solution, apparent viscosity of compound syetem remained 91% and 70% respectively.The Polysaccharide purified from Soracan gum inhibited melanin-tumor cells in vitro to a certain extent. And the antitumor activity increased gradually with the increase of polysaccharide concentration. When the concentration of polysaccharide reached 100μg/ mL, the inhibitory ratio reached the maximum (21%).