The skin is constantly exposed to external and internal factors that disturb its function. In this work, two nanosystems-levan nanoparticles and a surfactin-stabilized nanoemulsion were preserved (tested for microbial growth) and characterized (size, polydispersity, Zeta potential, and stability). The nanosystems were introduced in the model formulations-cream, tonic, and gel, and confirmed by TEM. The analysis showed that nanoemulsion has a spherical morphology and size 220–300 nm, while levan nanoparticles had irregular shapes independently of the use of matrix and with particle size (130–260 nm). Additionally, we examined the antiradical effect of levan nanoparticles and nanoemulsion in the prototype of formulations by scavenging DPPH (2,2-diphenyl-1-picrylhydrazyl; EPR spectroscopy). The model cream with both nanosystems and the whole range of products with nanosystems were evaluated in vivo for hydration, elasticity, smoothness, wrinkles and vascular lesions, discoloration, respectively. The cream improved skin condition in all tested parameters in at least 50% of volunteers. The use of more comprehensive care, additionally consisting of a tonic and gel, reduced the previously existing skin discoloration to 10.42 ± 0.58%. The presented prototype formulations are promising in improving skin conditions.

The implementation of sustainable development goals in the cosmetics industry is focused primarily on the phase of product design and the formulation of fully functional cosmetics based on raw materials of natural origin. The aim of the present study was to evaluate the feasibility of using a surfactin-rich digestate extract—a raw material of biotechnological origin—as an ingredient in cleansing cosmetics. A composition was designed, and shower gels based on the digestate extract were formulated. In the next stage of the study, the prototypical products were subjected to a quality assessment with an emphasis on the properties determining their functionality and safety of use by consumers. The shower gels formulated with raw materials of natural origin with the addition of the surfactin-rich extract show acceptable functional properties including viscosity, foaming ability and fat emulsification properties. Importantly, the use of the digestate extract was found to significantly improve the safety in use of the evaluated cosmetic prototypes. This finding is corroborated by a significant decrease in the zein value, which is a measure of the irritant effect of cosmetic formulations. A slight decrease in the ability to emulsify fats found for the tested prototypes confirmed their appropriate functionality and mild effect on the skin. Through the use of the surfactin-rich digestate extract, the cosmetics acquired a natural color derived from the extract. Colorimetric analysis shows that the color changes in the samples should be noticeable even by inexperienced observers. Graphical Abstract

Separating amphiphilic compounds from complex matrix is challenging. Surfactin, cyclic lipopeptides group, was used as a model to find the proper separation conditions and parameters. The aim of the work was to solve the emulsification plug problem in countercurrent partition chromatography (CPC). The selected solvent system was a composition of n-heptane/n-butanol/methanol/aqueous buffer (20 mM disodium phosphate with 50 mM NaCl) at a ratio of 2:3:2:3. Several elution method modifications were applied. The most important was an appropriate mobile phase flow rate adjustment (flow rate gradient), minimizing the risk of stationary phase leakage. During the CPC procedures, the hydrostatic pressure was monitored as a factor of stationary phase retention. The hydrostatic pressure indicated the biphasic system’s stability. A flow rate of 2 ml/min resulted in column stabilization and peak resolution during chromatographic separation. In order to avoid uncontrolled leakage, the flow rate was increased gradually. At 3.5 ml/min, there was a small loss of the stationary phase as the hydrostatic pressure decreased from 32 to nearly 18 bar. After designing the method, it was tested with SU containing extracts obtained from SSF to show its effectiveness. Our results showed that the single dual-mode method can be used to remove matrix’s impurities and separate surfactin as a mixture of homologues with more than 80% purity. Moreover, application of the double dual-mode method allows for the isolation of fractions containing individual surfactin homologues in amounts of about 70% of the sample, which makes it possible to conduct further biological research.

Surfactin, a group of cyclic lipopeptides produced by Bacillus subtilis, possesses surfactant properties and is a promising natural and biologically active compound. In this study, we present a comprehensive characterization of surfactin, including its production, chromatographic separation into pure homologues (C12, C13, C14, C15), and investigation of their physicochemical properties. We determined adsorption isotherms and interpreted them using the Gibbs adsorption equation, revealing that the C15 homologue exhibited the strongest surface tension reduction (27.5 mN/m), while surface activity decreased with decreasing carbon chain length (32.2 mN/m for C12). Critical micelle concentration (CMC) were also determined, showing a decrease in CMC values from 0.35 mM for C12 to 0.08 mM for C15. We employed dynamic light scattering (DLS), transmission electron microscopy (TEM), and density functional theory (DFT) calculations to estimate the size of micellar aggregates, which increased with longer carbon chains, ranging from 4.7 nm for C12 to 5.7 nm for C15. Furthermore, aggregation numbers were determined, revealing the number of molecules in a micelle. Contact angles and emulsification indexes (E24) were measured to assess the functional properties of the homologues, showing that wettability increased with chain length up to C14, which is intriguing as C14 is the most abundant homologue. Our findings highlight the relationship between the structure and properties of surfactin, providing valuable insights for understanding its biological significance and potential applications in various industries. Moreover, the methodology developed in this study can be readily applied to other cyclic lipopeptides, facilitating a better understanding of their structure-properties relationship.