Related Experiment Video
Updated: Feb 7, 2026

Measuring the Densities of Aqueous Glasses at Cryogenic Temperatures
Published on: June 28, 2017
Effect of temperature and shear on the microstructure of a microbial polysaccharide secreted by Sphingomonas species
M Carmen García1, José A Carmona1, Jenifer Santos1
1Departamento de Ingeniería Química, Facultad de Química, Universidad de Sevilla, C./P. García González, 1, E41012 Sevilla, Spain.
Abstract:
Diutan gum is a biological polymer produced by Sphingomonas sp. In aqueous solution it shows gel-like structure under quiescent conditions. However, the flow-induced evolution of its viscoelastic properties and its microstructure are not known. In this work, the viscoelastic moduli were obtained under a flow field, applied in parallel, as a function of the temperature for 0.5 wt% diutan gum aqueous solutions. As both stress and temperature increase a decrease in the viscoelastic properties occurred, due to the fact that the molecular interactions decreased. Nevertheless, at stresses within the zero-shear viscosity region of the flow curves, no changes were observed. In addition, high stress values dampened the effect of the temperature. The results obtained are very interesting from an industrial application perspective.
Related Concept Videos
Chemical Reactions in Aqueous Solutions
Aqueous Solutions and Heats of Hydration
When ionic compounds dissolve in water, the ions in the solid separate and disperse uniformly throughout the solution because water molecules surround and solvate the ions, reducing the strong electrostatic forces between them. This process...
Leveling Effect and Non-Aqueous Acid-Base Solutions
The Leveling Effect of a Solvent
A generic acid (HA) reacts with the generic base (B-) to yield the corresponding conjugate base (A-) and conjugate acid (HB):
Factors Influencing Microbial Growth: Temperature
Biosynthesis of Polysaccharides
Physical Methods for Controlling Microbial Growth: Temperature

