Physicochemical properties of the exopolysaccharides produced by marine bacterium Zoogloea sp. KCCM10036.

The physicochemical properties of the exopolysaccharide (EPS) produced by marine bacterium Zoogloea sp. KCCM10036 were investigated. Two types of isolated EPSs were shown to have average relative molecular masses (Mr) of 4.07 x 10(6) of CBP (cell-bound polysaccharide) and 3.43 x 10(6) of WSP (water-soluble polysaccharide), respectively. When the CBP was utilized as an emulsifier, it stabilized the emulsion for up to 148 h. Compared with other commercially available hydrocolloids such as xanthan gum, the Tween series, and Triton, the CBP showed much better emulsifying capability on a water-in-oil system. Phase separation occurred in the Tween series after 24 h, whereas the emulsion was better stabilized by the CBP. The CBP thus has potential as an emulsifying agent in commercial emulsions. The flocculating activity was also greatest at 0.01% (w/v) and decreased at higher concentrations than the optimized concentration of the WSP and CBP. The results also showed that both types of exopolysaccharides from Zoogloea sp. had excellent flocculating activity.