Ultrasonic and free-radical degradation of mannan from Candida albicans

Area of Science:

• Biochemistry
• Polymer Chemistry
• Microbiology

Background:

• Mannan, a polysaccharide from Candida albicans, is a key virulence factor.
• Degradation of mannan can impact fungal pathogenicity.
• Developing controlled methods for mannan degradation is of interest.

Purpose of the Study:

• To investigate the degradation of Candida albicans serotype A mannan using ultrasound and Fenton reaction.
• To compare the efficiency and outcomes of these two degradation methods.
• To characterize the resulting mannan fragments in terms of molecular weight and structural integrity.

Main Methods:

• Degradation of mannan using ultrasonication and/or in situ hydroxyl radical (OH) generation via Fenton reaction.
• Monitoring degradation kinetics using High-Performance Liquid Chromatography (HPLC).
• Analysis of weight-average molecular weight (Mw) and index of polydispersity (PDI) using gel permeation chromatography.
• Structural characterization of degraded mannan using Nuclear Magnetic Resonance (NMR) spectroscopy.

Main Results:

• Ultrasonication for 120 minutes yielded a well-defined low-molecular-weight mannan (Mw ~30 kDa) with a narrowed PDI of 1.8.
• Fenton reaction-based free-radical exposure achieved similar or lower Mw (up to 16 kDa).
• Free-radical degradation resulted in broader PDI and distinct structural changes in the mannan polymer, as evidenced by NMR analysis.

Conclusions:

• Both ultrasound and Fenton reaction are effective in degrading Candida albicans mannan.
• Ultrasonication offers a controlled method for obtaining low-Mw mannan with narrow PDI.
• Fenton reaction provides a route to very low Mw mannan but leads to significant structural alterations.