Curdlan obtained from

Figure 2. Resilient gel obtained from curdlan at temperatures in excess of 95°C...

Figure 3. X-ray fiber diffraction photograph obtained from a dry, annealed-oriented fiber of curdlan gel (fiber axis vertical)...

Figure 4. X-ray diffraction photographs of curdlan fibers obtained from alkali solution (a) at 100% relative humidity (b) after drying over silica gel (c) after...

The dimensions of the xylan unit cell are slightly different a = b = 1.340 nm, (fibre axis) = 0.598 nm.) Atkins and Parker T6) were able to interpret such a diffraction pattern in terms of a triple-stranded structure. Three chains, of the same polarity, intertwine about a common axis to form a triple-strand molecular rope. The individual polysaccharide chains trace out a helix with six saccharide units per turn and are related to their neighbours by azimuthal rotations of 2ir/3 and 4ir/3 respectively, with zero relative translation. A similar model for curdlan is illustrated in Figure 6. Examinations of this model shows that each chain repeats at a distance 3 x 0.582 = 1.746 nm. Thus if for any reason the precise symmetrical arrangement between chains (or with their associated water of crystallization) is disrupted, we would expect reflections to occur on layer lines which are orders of 1.746 nm. Indeed such additional reflections have been observed via patterns obtained from specimens at different relative humidity (4) offering confirmation for the triple-stranded model. 

Figure 8. IR spectra obtained from curdlan sample gelled in water (a) original film (b) film after deuteration (c) rehydrogenated film...

Figure II. IR spectrum obtained from gelling curdlan in DtO...

The polymers such as cellulose, curdlan, xanthan, levan, and dextran that are obtained from the respective bacteria as described in section 10.2 are utilized in various food applications. Cellulose is used in food (nata de coco), and curdlan is used in food as a thickener and gelling agent. Dextran is used in healthy beverages, xanthan is used as a rheology modifier and food additive, and levan is used in food biotechnology. 

Ref. 112 with permission. (C) (a) A plot of the intensity changes of C-6 and C-3 signals (%) in curdlan against temperature with reference to those obtained in the presence of 0.3 M NaOH. (b) a plot the C-3 13C chemical shift against temperature. From Ref. 9. 

NMR spectroscopy allowed to determine that the native SSG glucan from Sclerotinia sclerotiorum IFO 9395 and regenerated SSG obtained by neutralization of the alkaline solution had different conformations, since their C-3 signals appeared at 86 and 89 ppm, respectively. These values imply that while regenerated SSG possesses helical structure similar to that of curdlan, the native SSG in solid state has random-coil conformation [69]. 

Agarose gel, which exhibits elasticity similar to that of Curdlan, clearly provides signals from the solution-like region as shown in the upper C DD-MAS spectrum of Fig. 6 [130]. However, a spectrum similar to this can also be obtained by the CP-MAS technique as shown in the bottom spectrum of Fig. 6 (the solid-like region). However, there appears to be a difference in the 77-78.5 ppm resonance, which is the characteristic region of polysaccharide chains. Unlike in the solid-like region, this difference is thought to arise from the random coil structure in... 

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