PHYSICAL PROPERTIES AND CHEMICAL COMPOSITION OF BETA-GLUCANS FROM FLESHY FUNGI

Area of Science:

• Microbiology
• Biochemistry
• Polymer Science

Background:

• Fungal fermentation produces complex polysaccharides with potential industrial applications.
• Understanding the structure-property relationships of these biopolymers is crucial for their utilization.

Purpose of the Study:

• To characterize the physical properties and chemical structures of two related polysaccharides from Plectania occidentalis and Helotium sp.
• To investigate the impact of environmental factors on polysaccharide stability and viscosity.

Main Methods:

• Fermentative production of polysaccharides.
• Precipitation and redissolution for solution preparation.
• Viscosity measurements, including thixotropic behavior analysis.
• Chemical structure elucidation via acid hydrolysis, periodate oxidation, and chromatography.
• Stability testing under varying pH and temperature conditions.

Main Results:

• Both polymers yielded amorphous gels, forming stable aqueous solutions up to 1.5% concentration.
• Viscosity ranged from 50 to 2,200 centipoises, with thixotropic properties at higher concentrations.
• Salts (except borate) had minimal effect on viscosity; borate slightly increased it.
• Polysaccharides were stable in neutral solutions and at moderate pH but degraded under extreme pH at elevated temperatures.
• Structural analysis revealed both are branched glucans with significant beta-1,3 linkages.

Conclusions:

• The studied fungal polysaccharides are structurally related branched glucans with notable beta-1,3 linkages.
• Their physical properties, including viscosity and thixotropy, are consistent across different fungal sources.
• The polymers demonstrate good stability under typical processing conditions, with limitations at extreme pH and temperature.