Synthesis and characterisation of microbial acylated amino acids as potential biosurfactants

Current synthesised surfactants available commercially have adverse effects on the environment due to their high toxicity and persist in the environment due to their low biodegradability. The need for sustainable and more eco-friendly alternatives to current surfactants is high and biosurfactants may be the solution. In this project, acylated amino acid biosurfactants being N-palmitoyl-L-valine and N-stearoyl-L-valine was synthesised to explore their surfactant properties as a potential alternative. The emulsification index was determined by E24 testing and it was observed that it can be considered a promising emulsifier which is a key surfactant property. Diffusion-ordered spectrometry (DOSY, NMR) was carried out on varying concentrations of these surfactants to determine their critical micelle concentration (CMC). The CMC is important in determining the aqueous solubility and dissolution of surfactant to efficiently reduce surface tension of liquid interfaces. The CMC is achieved in N-palmitoyl-L-valine with a lower concentration of surfactant compared to a common commercially used surfactant, sodium dodecyl sulphate, therefore this biosurfactant can also be considered to have excellent aqueous solubility and dissolution where smaller amounts can be used to reduce surface tension of liquid interfaces. Overall, N-palmitoyl-L-valine is a promising potential biosurfactant