Plant cell cultures for the cosmetics industry

An alternative is the use of plant cells in suspension culture, which are exposed to standardized and controlled conditions. Fraunhofer IME received a contract from a cosmetics company in Aachen to generate plant cell cultures from the fruits of the pear variety “Champagner Bratbirne” (Pyrus communis cv. Champagner Bratbirne) and from the wild service tree (Sorbus torminalis). Furthermore, the process was to be suitable for production at a 20–50 kg scale.

First, the researchers sterilized the surfaces of the fruits from both plants to remove unwanted microbes. Under sterile conditions, they cultured the fruit tissue on a nutrient medium. In addition to sugar as a nutrient source, the medium contained various plant hormones that induce undifferentiated cell growth from the fruit tissue. This resulted in cell clusters, which were then further cultivated in liquid medium. Continuous agitation caused the cells to form smaller aggregates or single cells. Because these undifferentiated cells can regenerate into intact plants when specific plant hormones are added, the cosmetics industry also refers to these cell cultures as plant stem cells.

The next step was production optimization. The biotechnologists used Design of Experiments (DoE) for this purpose. In the past, laboratory work was dominated by intuitive approaches, such as changing one factor at a time or trial-and-error methods. These approaches, however, only randomly achieve optimal results, as the individual and interactive effects of influencing factors are not recognized. In contrast, statistical experimental design allows for systematic planning and statistical evaluation of experiments. With minimal effort, the functional relationship between influencing parameters and outcomes can be determined and mathematically described. The advantage of statistical experimental design is that multiple factors—such as temperature, concentration, or culture duration—can be evaluated simultaneously to analyze the conditions under which product properties or “responses,” such as yield, reach optimal values.

Using this method, the researchers were able to increase cell yield by 300% over a cultivation period of seven to fourteen days, reduce unwanted by-products such as lipids and polysaccharides to <5%, and cut production costs by a factor of three. Before use in selected cosmetics, the cells are separated from the medium by filtration, disrupted in a homogenizer, and insoluble components are removed by centrifugation. Finally, the clear cell extract is mixed with alcohol, and the product can be incorporated into selected cosmetics, such as creams.

In this case, the use of plant cells in suspension culture represents an attractive alternative to using intact plants, offering multiple advantages. Controlled cultivation conditions can, for example, prevent microbial contamination through endotoxins, and the use of plant protection agents can be avoided, benefiting both the environment and product quality. Moreover, such cell cultures are independent of climate conditions, seasons, or geopolitical factors, ensuring continuous production.

Through collaboration with Fraunhofer IME, the company Babor gained a new sustainable source of extracts from the wild service tree. The continuous availability allows for the mitigation of seasonal harvest failures and supply shortages. Dr. Babor uses exclusive stem cell extracts from the wild service tree in the product line “SPA Shaping.”