Rhamnolipid Self-Aggregation in Water-Bioglycerol Mixtures: Byproduct Valorization for Sustainable Formulation Design

Area of Science:

• * Sustainable Chemistry
• * Materials Science
• * Biotechnology

Background:

• * Biodiesel production yields significant quantities of bioglycerol, a versatile byproduct.
• * Bioglycerol's potential applications are expanding, particularly as a cosolvent in industrial formulations.
• * Eco-sustainable formulation design necessitates understanding the behavior of key components like biosurfactants in bioglycerol mixtures.

Purpose of the Study:

• * To investigate the self-aggregation behavior of rhamnolipids in aqueous bioglycerol mixtures.
• * To assess the impact of bioglycerol concentration and impurities on rhamnolipid aggregation.
• * To provide foundational knowledge for utilizing rhamnolipids and bioglycerol in sustainable formulations.

Main Methods:

• * Surface tension measurements to analyze interfacial properties.
• * Nuclear Magnetic Resonance (NMR) self-diffusion measurements to probe molecular dynamics and aggregation.
• * Characterization of water-bioglycerol mixtures, including analysis of impurities' effects.

Main Results:

• * Bioglycerol impurities (potassium acetate) showed minimal impact on surface tension and bulk properties.
• * Rhamnolipid aggregation remained largely unaffected in bioglycerol mixtures up to 40-50 wt%.
• * At higher bioglycerol concentrations (>50 wt%), critical micelle concentration (cmc) increased, and micelle size decreased due to reduced medium polarity.

Conclusions:

• * Rhamnolipids exhibit stable aggregation in a wide range of bioglycerol concentrations, suitable for formulation development.
• * The study provides essential data for the effective use of rhamnolipids and bioglycerol in eco-sustainable industrial applications.
• * Understanding these interactions is key to unlocking the full potential of bioglycerol as a formulation ingredient.