Probiotic bacteria confer health benefits to their host, support the intestinal microbiome and fight antibiotic resistance. Probiotic products are used in the food and pharmaceutical industries and, in recent years, have become increasingly popular in the cosmetic industry. However, in the case of cosmetics, it is difficult to meet microbiological requirements while maintaining viable cells. The aim of this research study was to develop an effective way of introducing live bacteria (a strain of L. casei) into cosmetic formulations. A method of encapsulation of the bacteria was used to increase their viability. As part of the results, the effective carriers for the strain of L. casei are reported. Alginate microspheres were prepared for the systems to protect the microorganisms against external factors, such as temperature, UV light and preservatives. The obtained probiotic-loaded alginate microspheres were then used as the active ingredient of cosmetic formulations. Additionally, a preservative system was carefully selected to ensure the microorganisms’ viability and the microbiological stability of the products. The obtained results showed a significant improvement in the survival of the microencapsulated probiotic strain in the cosmetic formulations containing antimicrobial agents (6.13 log CFU/g after 120 days of storage) compared with the formulation containing the non-immobilised probiotic strain, where complete elimination of bacterial cells was observed.

The purpose of this study was to explore the possibility of replacing an expensive yeast extract contained in the fermentation medium for D-lactic acid (D-LA, R-lactic acid) biosynthesis with an alternative nitrogen source. The screening studies were conducted under stationary conditions and showed that pea seed hydrolysate was the most beneficial substrate in the process of D-LA biosynthesis by the strain Sporolactobacillus laevolacticus DSM 442 among the used inorganic and organic nitrogen sources, waste materials, food and agricultural products. After 96 h, 75.5 g/L D-LA was obtained in batch cultures in a medium containing pea seed hydrolysate, with an average productivity of 0.79 g/L/h, yield of 75.5%, and optical purity of 99.4%. In batch cultures fed once, in a medium with an analogous composition, 122.6 g/L D-LA was obtained after 120 h, and the average yield, productivity and optical purity were 87.6%, 1.021 g/L/h, and 99.6%, respectively. Moreover, the amount of D-LA obtained in the fermentation medium enriched with the above-mentioned cheap agricultural product was similar to the amounts obtained in the medium containing yeast extract in both stationary and bioreactor cultures. Our research shows that hydrolyzed pea seeds, which belong to the legume family, may be a promising nitrogen source for the production of D-LA on an industrial scale.

Oleogels (organogels) are systems resembling a solid substance based on the gelation of organic solvents (oil or non-polar liquid) through components of low molecular weight or oil-soluble polymers. Such compounds are organogelators that produce a thermoreversible three-dimensional gel network that captures liquid organic solvents. Oleogels based on natural oils are attracting more attention due to their numerous advantages, such as their unsaturated fatty acid contents, ease of preparation, and safety of use. As a result of the research, two oleogels were developed, into which freeze-dried alginate carriers with a probiotic, L. casei, were incorporated. Two techniques were used to produce probiotic-loaded capsules—extrusion and emulsification. Alginate beads obtained by the extrusion process have a size of approximately 1.2 mm, while much smaller microspheres were obtained using the emulsification technique, ranging in size from 8 to 17 µm. The trehalose was added as a cryoprotectant to improve the survival rate of probiotics in freeze-dried alginate carriers. The encapsulation efficiency for both of the methods applied, the emulsification and the extrusion technique, was high, with levels of 90% and 87%, respectively. The obtained results showed that the production method of probiotic-loaded microspheres influence the bacterial viability. The better strain survival in the developed systems was achieved in the case of microspheres produced by the emulsification (reduction in bacterial cell viability in the range of 1.98–3.97 log in silica oleogel and 2.15–3.81 log in sucragel oleogel after 7 and 30 days of storage) than by the extrusion technique (after a week and a month of oleogel storage, the decrease in cell viability was 2.52–4.52 log in silica oleogel and 2.48–4.44 log in sucragel oleogel).

The process of obtaining alginate microspheres (AMs) by emulsification method was optimized by applying statistical analysis software. Ten batches of microspheres were prepared using the fractional plan 3 (K-p). AMs were obtained with two different methods: an ultrasonic homogenization (UH) process and a rotor-stator mechanical homogenization (MH). The amount of a cross-linking agent (CaCl 2), calcium chloride rate addition, and the sonication amplitude (UH) or the speed of rotor rotation (MH) were selected as formulation variables. All the batches were evaluated in terms of stability and size of the alginate microspheres. Approximation profiles were developed. As a result of the conducted research, stable alginate microspheres with sizes ranging from 10 to 30 micrometres were obtained. The obtained results showed that the quality of AMs was mainly affected by the concentration and the rate of calcium chloride addition into the system. Therefore, the role of calcium ions in the mechanisms of shell structuring was discussed. Lactobacillus casei bacteria were encapsulated into the batches found to be optimum. The high encapsulation efficiency (EE) of the bacteria (72-94%) depending on the form) and their viability over time were obtained. The model developed in the study can be effectively utilized to achieve the AMs formulations.

Skin microbiome-friendly preparations are gaining increasing popularity in the cosmetics and pharmaceutical industries. Fermented plants, lysates, and heat-treated products are used as probiotic ingredients in cosmetics. This is due to the presence of Lactobacillus bacteria, such as acid or acid-rennet whey, which are natural probiotics that can positively impact the skin microbiome. However, due to technological difficulties, the direct use of whey as a cosmetic ingredient is limited. An optimized emulsification method was used to obtain alginate microspheres as carriers of whey. The process parameters were optimized using the Design of Experiments (DoEs) methodology. The effect of three key variables, including the type of probiotic raw material (whey from 1—cows, 2—goats, and 3—mixed), the alginate-to-raw material ratio (1–3%), and sonication time (0.5–1.5 min), on parameters such as encapsulation efficiency, bacterial survival, viscosity, and microspheres size was analyzed. The results obtained demonstrated that the optimal process parameters were the sonication time of 0.5 min and the alginate-to-whey mass ratio of 1.5% for all types of whey material studied. However, the most important factor influencing the properties and functionality of the microspheres was sonication time. The optimized whey-loaded microspheres were incorporated into a preservative-containing emulsion system, in which the viability of whey-derived bacteria was monitored over time. The whey encapsulation process effectively maintained the bacteria’s probiotic properties, protecting their viability despite the presence of preservatives (at a level of 4.92 ± 0.9 log CFU/g after 30 days of formulation storage), thus confirming the feasibility of incorporating liquid whey into skincare formulations.