• Korean Journal of Microbiology
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• v.33 no.3
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• pp.187-192
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• 1997

The strain producing biosurfactant was isolated from soil. The isolated strain was identified as the genus Tsukamurella through its morphological, cultural, physiological, menaquinone type, fatty acid composition characteristics. The highest biosurfactant production by Tsukamurella sp. 26A was observed after 4 days cultivation in the culture medium containing n-hexadecane 7%, $NaNO_{3}$ 0.2%, $K_2HPO_4$ 0.001%, $MgSO_{4}$ center dot $7H_{2}O$ 0.02%, $CaCl_2$ center dot $2H_{2}O$ 0.02%, yeast extract 0.02%(pH 6.8-7.0, 30^{\circ}C.$ The surface and interfacial tension of an aqueous solution reached 30 mNim and 1.5 mNim, respectively. The biosurfactant stabilized oil-in-water emulsion with a variety of hydrocarbons, edible oils and petroleum oils.

• Journal of Microbiology and Biotechnology
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• v.9 no.1
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• pp.32-38
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• 1999

A biosurfactant produced by Tsukamurella sp. 26A was purified by procedures including acid precipitation, ethylacetate extraction, and adsorption chromatography. The purified biosurfactant reduced the surface tension of water from 72 mN/m to 30 mN/m at a concentration of 250 mg/l, whereas the minimum interfacial tension against n-hexadecane was lowered to 1.5 mN/m at a concentration of 40 mg/i. The compound stabilized oil-in-water emulsions with a variety of commercial oils and had strong emulsification and stabilization activities when compared to those of commercial emulsifiers and stabilizers. Surface tension was stable over a broad range of pH (2-12) and temperature ($100^{\circ}C$, 3h). The biosurfactant was identified as glycolipid having a hydrophilic moiety of trehalose.