Polysaccharide structures and interactions in a lithium chloride/urea/water solvent

Area of Science:

• Biochemistry
• Materials Science
• Polymer Chemistry

Background:

• Molten salt hydrates like lithium chloride (LiCl)/urea/water are known cellulose swelling agents.
• Previous research focused on cellulose, leaving effects on other polysaccharides unexplored.

Purpose of the Study:

• Investigate the solvent effects of LiCl/urea/water on four natural polysaccharides.
• Determine how polysaccharide structure influences their behavior in this solvent.
• Analyze polysaccharide binding interactions with cellulose in different solvent conditions.

Main Methods:

• Viscosity measurements of fenugreek gum, xyloglucan, konjac glucomannan, and locust bean gum (LBG) in water and LiCl/urea/water.
• Confocal microscopy to assess polysaccharide binding to cellulose.

Main Results:

• Highly branched polysaccharides (fenugreek gum, xyloglucan) increased in viscosity, likely due to disrupted intra-molecular associations.
• Unbranched konjac glucomannan viscosity remained unchanged.
• Locust bean gum (LBG) viscosity decreased due to aggregate disruption.
• Fenugreek gum lost cellulose-binding ability in LiCl/urea/water, while xyloglucan gained it.
• Konjac glucomannan showed no cellulose binding in either solvent.

Conclusions:

• Polysaccharide fine structure significantly influences conformational changes in LiCl/urea/water.
• Solvent environment and inherent polysaccharide structure dictate cellulose-binding capabilities.
• These findings offer new perspectives on polysaccharide-solvent interactions and their structural implications.