Solution properties and chain flexibility of pullulan in aqueous solution

✍ Scribed by Tadaya Kato; Toshihiro Okamoto; Tadashi Tokuya; Akira Takahashi

• Publisher: Wiley (John Wiley & Sons)
• Year: 1982
• Tongue: English
• Weight: 524 KB
• Volume: 21
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.360210812

✦ Synopsis

Molecular characteristics for pullulan, a polysaccharide produced by a fungus Aureobasidium pullulans, were measured by light scattering, viscometry, and gel-permeation chromatography. From the experimental data the Mark-Houwink-Sakurada viscosity equation in water a t 25OC was determined for samples having the molecular weight A4 ranging from 48 X lo3 to 2.18 X lo6 g mol-I as [77] = (1.91 + 0.02) X 10-2M0,;""0.0' (in cm3 g-l); and as molecular weight decreased, the slope of the viscosity equation decreased, although the molecular weight values below 30 X lo3 g mol-' evaluated by gel-permeation chromatography were somewhat unreliable. The unperturbed dimensions (R') t2 of pullulan were estimated by determining the expansion factor as from the theoretical combination of theories for the interpenetration function 9 and those for a,. The (RZ)dM value estimated from this procedure is 6.7 X 1O-l' cm2 mol g-I. We concluded that the polysaccharide chain that is linked by the a-1,6-glucosidic linkage behaves like a flexible chain in aqueous solution.