Characterization and Emulsification Properties of Rhamnolipid and Sophorolipid Biosurfactants and Their Applications

Thu T Nguyen,David A Sabatini

doi:10.3390/ijms12021232

Thu T Nguyen, David A Sabatini

Open Access

https://doi.org/10.3390/ijms12021232

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Abstract

Due to their non-toxic nature, biodegradability and production from renewable resources, research has shown an increasing interest in the use of biosurfactants in a wide variety of applications. This paper reviews the characterization of rhamnolipid and sophorolipid biosurfactants based on their hydrophilicity/hydrophobicity and their ability to form microemulsions with a range of oils without additives. The use of the biosurfactants in applications such as detergency and vegetable oil extraction for biodiesel application is also discussed. Rhamnolipid was found to be a hydrophilic surfactant while sophorolipid was found to be very hydrophobic. Therefore, rhamnolipid and sophorolipid biosurfactants in mixtures showed robust performance in these applications.

Highlights

Rhamnolipid (Figure 1) and sophorolipid (Figure 2) biosurfactants are glycolipid biosurfactants which are generally composed of carbohydrate heads and lipid tails [1,2]
Rhamnolipid biosurfactants discussed in this review were produced by Pseudomonas aeruginosa growing on glucose
The results show that for all four studied surfactant mixtures, the optimum salinity increases with increasing JBR molar fraction and is highest at 100% JBR in mixtures, suggesting that rhamnolipid biosurfactant is more hydrophilic than all four studied surfactants

Summary

Introduction

Rhamnolipid (Figure 1) and sophorolipid (Figure 2) biosurfactants are glycolipid biosurfactants which are generally composed of carbohydrate heads and lipid tails [1,2]. 2011, 12 two hydrophilic head groups: the carboxylate group that gives the rhamnolipids an anionic character and the rhamnosyl that contributes to the bulkiness of the head group. Sci. 2011, 12 two hydrophilic head groups: the carboxylate group that gives the rhamnolipids an anionic character and the rhamnosyl that contributes to the bulkiness of the head group This review focuses on the lactone acetylated sophorolipid biosurfactants, produced by Candida bombicola growing on a mixture of glucose and fatty acids, palmitic and oleic acids. This article reviews the technique to characterize the hydrophilicity/hydrophobicity of these two biosurfactants and the evaluation of their microemulsion formation for a range of oils. Type IV microemulsions are the expansion of the middle phase microemulsions at high surfactant concentration such that all the excess oil and excess water are incorporated into a single phase. The use of rhamnolipid and sophorolipid biosurfactants in detergency and vegetable oil extraction for biodiesel application is exclusively reviewed

Characteristic Curvature and Rhamnolipid Characterization

Applications

Conclusions