Polysaccharides are found in plants, animals, fungi, and microorganisms, serving crucial roles like energy storage, structure, and defense. They are classified into homopolysaccharides (composed of one type of monosaccharide) and heteropolysaccharides (composed of multiple types of monosaccharides). Most of the biosynthesized polysaccharides are inherently heterogeneous, having wide distribution in molecular weights, branching patterns, linkage conformations, and degrees of substituents. This heterogeneity affects research results where the structure-activity relationship becomes difficult to infer. Therefore, it is very crucial to fractionate polysaccharides into more homogeneous fractions.
Fractionation methods
Different methods like chromatography, ultrafiltration, and gradient non-solvent precipitation help achieve polysaccharide uniformity.
- Chromatography: Uses columns with specific molecular weight cut-off
- Ultrafiltration: Uses membranes with specific molecular weight cut-off
- Non-solvent fractional precipitation: Gradual addition of a non-solvent to a polysaccharide solution causes gradual precipitation.
Chromatography and ultrafiltration have limitations due to equipment costs and scalability issues. On the other hand, non-solvent fractional precipitation uses simple equipment like stirred tanks and is more scalable and versatile for different polysaccharides. This method is reviewed for its potential in preparative fractionation of polysaccharides.
Advantages of Gradient Non-Solvent Precipitation
- Simple Equipment: Requires only basic equipment like stirred tanks.
- Scalability: Easily scalable for large or small preparations.
- Versatility: Applicable to various polysaccharides with different molecular weights.
- Cost-Effective: Lower equipment and operational costs compared to chromatography and ultrafiltration.
