Effect of Polysaccharide Conformation on Ultrafiltration Separation Performance.

Area of Science:

• Polymer Science
• Membrane Science
• Biochemistry

Background:

• Polysaccharides exhibit diverse structures and conformations (sphere, coil, rod) in solution.
• Standard molecular weight cut-off (MWCO) is unreliable for polysaccharides due to their varied shapes, unlike globular proteins.

Purpose of the Study:

• To investigate the effect of polysaccharide conformation on ultrafiltration performance.
• To compare membrane rejection and molecular weight distribution for different polysaccharide shapes.

Main Methods:

• Utilized pullulan (random coil) and scleroglucan (rigid rod) as model polysaccharides.
• Performed ultrafiltration using a 10 kDa polyethersulfone membrane.
• Analyzed polysaccharide recovery and molecular weight distribution post-filtration.

Main Results:

• Recoveries varied significantly: 1% for pullulan vs. 71% for scleroglucan.
• Observed over 77-fold discrepancies between nominal MWCO and apparent molecular weights.
• Achieved >90% recovery of polysaccharides with unchanged molecular weights.

Conclusions:

• Polysaccharide conformation is a critical factor in ultrafiltration membrane performance.
• Current MWCO criteria are inadequate for precise polysaccharide separation.
• Findings pave the way for optimized membrane selection for polysaccharide applications.