Kevwords: Aureobasidium: pu/lu/ans: pullularia: polysaccharides: pseudoplastic: apparent viscosity: rolling-ball viscometer: Stokes' law: power-law equation
نویسندگان
چکیده
A rolling-sphere viscometer (RSV) was constructed and evaluated for monitoring apparent viscosit~'es of fermentation broths in sha'ke flasks or test tubes. The apparatus was calibrated by measuring translational velocities of magnetic stainless ste.el spheres (0.16-0.95 em diameter) rolling in N~wto nian viscosity standards (50-12.500 mPa's) on surfaces inclined 20° to 70°. The method was applted to fermentatio~ broths of Aureobasidium pullulans. Apparent viscosities fit the power-law equation. Maximum viscosities and minimum power-law indices were reached within 4 to 6 days fermentatIOn time. followed by a decrease in viscosity.
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