• Journal of Life Science
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• v.27 no.8
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• pp.930-936
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• 2017

The flocculating properties of bioflocculant Biopol32 produced by Pseudomonas sp. GP32 were investigated for application in industrial wastewater treatment. The major flocculating substance of bioflocculant Biopol32 was identified as polysaccharide. Many anionic flocculants need a counter ion to induce higher flocculating activity. The flocculating activity of bioflocculant Biopol32 was markedly increased by the addition of cationic ions ($Ca^{2+}$, $Al^{3+}$). The flocculating activity of bioflocculant Biopol32 was the most effective when 7.0 mM $CaCl_2{\cdot}2H_2O$ as coflocculant was added. The flocculating activity on the effect of pH and the temperature of the bioflocculant Biopol32 was compared with anionic commercial flocculant (polyacrylamide) and bioflocculant (zooglan from Zoogloea ramigera). In kaolin suspension, the highest flocculating activity was obtained at the bioflocculant Biopol32 concentration of 1.5 mg/l. A high flocculating activity was observed in the pH range of 5.0 to 8.0. The flocculating activity of bioflocculant Biopol32 was sustained up to $60^{\circ}C$, but decreased rapidly at over $70^{\circ}C$. In the batch culture, the charge density of bioflocculant Biopol32 was compared with flocculating activity. The larger the anionic charge density and apparent viscosity of bioflocculant Biopol32, the higher the flocculating activity. Therefore, we confirmed that the flocculating activity and apparent viscosity of bioflocculant Biopol32 was closely related to the charge density of bioflocculant Biopol32.

• Journal of Microbiology and Biotechnology
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• v.8 no.6
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• pp.618-624
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• 1998

The culture conditions for Bacillus sp. DP-152 in the flask were investigated for the production of polysaccharide locculant, DP-152. The optimum pH and temperature for the locculant production were 8.0 and $30^{\circ}C$, respectively. The avorable substrates for flocculant production were soluble tarch and ammonium nitrate. The medium composition was optimized as follows: 30 g soluble starch, 0.75 g $NH_4NO_3,\; 2.0g\; K_2\;HPO_4,\; 0.1\; g KH_2PO_4,\; 0.2g\; MgSO_4.\; 7H_2O,\; and\; 0.2g\; MnSO_4~5H_2O$ in 11 of distilled water. Under this optimized condition, flocculating activity has been improved 4-fold compared with that of the basal medium. In the culture flask, the highest flocculating activity was obtained after 70 h of cultivation and the amount of bioflocculant DP-152 yielded was 12.4 g/$\ell$. The solution of bioflocculant DP-152 showed non-Newtonian characteristics. Bioflocculant DP-152 exhibited apparently higher viscosity at all concentrations compared to that of zooglan (from Zoogloea ramigera), and it was stable over a wide range of temperatures and pHs.

• Journal of Life Science
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• v.25 no.9
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• pp.1027-1035
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• 2015

A strain GP32 which produces a highly viscous extracellular polysaccharide was conducted with soil samples and identified as Pseudomonas species. The culture flask conditions for the production of extracellular polysaccharide by Pseudomonas sp. GP32 were investigated. The most suitable carbon and nitrogen source for extracellular polysaccharide production were galactose and (NH₄)₂SO₄. The optimum carbon/nitrogen ratio for the production of extracellular polysaccharide was around 50. The optimum pH and temperature for extracellular polysaccharide production was 7.5 and 32℃, respectively. In batch fermentation using a jar fermentor, the highest extracellular polysaccharide content (15.7 g/l) was obtained after 70 hr of cultivation. The extracellular polysaccharide produced by Pseudomonas sp. GP32 (designated Biopol32) was purified by ethanol precipitation, cetylpyridinium chloride (CPC) precipitation, and gel permeation chromatography. Biopol32, which has an estimated molecular weight of over 3×10⁷ datons, is a novel polysaccharide derived from sugar components consisting of galactose, glucose, gulcouronic acid and galactouronic acid in an approximate molar ratio of 1.85 : 3.24 : 1.00 : 1.42. The solution of Biopol32 showed non-Newtonian characteristics. The viscosity of Biopol32 exhibited appeared to be higher at all concentration compared to that of zooglan from Zoogloea ramigera. An analysis of the flocculating efficiency of Biopol32 in industry wastewater (food, textile, and paper wastewater) revealed chemical oxygen demand (COD) reduction rates 58.4-67.3% and suspended solid (SS) removal rates 82.6-91.3%. Based on these results, Biopol32 is a possible candidate for industrial applications such as wastewater treatment.