Differences in levan nanoparticles depending on their synthesis route: Microbial vs cell-free systems

Area of Science:

• Biochemistry
• Polymer Science

Background:

• Levan, a polysaccharide, can be produced via microbial fermentation or cell-free enzymatic synthesis.
• Understanding the structural and aggregation properties of levan from different sources is essential for its application.

Purpose of the Study:

• To investigate and compare the physicochemical properties of levan synthesized through microbial and cell-free systems.
• To analyze differences in nanoparticle formation, thermal stability, and aggregation behavior.

Main Methods:

• Characterization of levan using nitrogen adsorption-desorption isotherms (BET analysis).
• Thermal analysis via thermogravimetric analysis (TGA).
• Determination of nanoparticle size and critical aggregation concentration (CAC).

Main Results:

• Both microbial and cell-free levans are non-porous solids (BET surface area ~20 m²/g) with thermal decomposition around 200°C and low protein adsorption.
• Microbial levan formed 90 nm nanoparticles, while cell-free levan yielded 110 nm nanoparticles.
• Critical aggregation concentrations differed: 0.05 mg/mL for microbial levan and 0.24 mg/mL for cell-free levan, with aggregate molecular weights exceeding 2000 kDa.

Conclusions:

• Levan from microbial and cell-free systems exhibit distinct aggregation behaviors and nanoparticle sizes.
• Aggregation equilibrium is a key characteristic of both levan types, influencing their properties and potential applications.
• Synthesis method significantly impacts levan's aggregation concentration, a critical parameter for formulation and use.