From Slovakia to new worlds

The path to new worlds leads through an idyllic valley in the middle of Slovakia. Here, at the foot of the Low Tatras, Evonik opened its new production plant for rhamnolipids at the end of May. Surrounded by nature and close to the Hron River, the plant is the only facility in the world that can produce high-purity rhamnolipids on an industrial scale. Evonik has chosen the site in Slovenská Ľupča, Slovakia, because the plant there already has decades of experience with fermentation processes. This biological production process is the key to sustainable production of the special lipids.

They did not start from scratch: the related sophorolipids have been produced here for a long time. They were the first microbiological biosurfactants to enter the market for beauty and personal care products. With the construction of the production plant for rhamnolipids, Evonik's researchers, developers and plant engineers have successfully conquered new territory. The task now is to explore the numerous applications that this product makes possible.

The active principle of surfactants is basically simple. They consist of hydrophilic, i.e. water-loving, and lipophilic, i.e. fat-loving, parts. This is why they arrange themselves in water in a special order: hydrophilic on the outside, lipophilic on the inside - in this arrangement they form a micelle above a certain concentration, the CMC (critical micelle concentration). When rinsing, for example, the fat-loving part adheres to the dirt, the hydrophilic part to the water. This means that the greasy dirt remains in the dishwater and plates and glasses come out clean.

The outstanding properties of rhamnolipids in terms of washing power were the reason for their first big step onto the market. They have already more than proven themselves in dishwashing detergents. Rhamnolipids are particularly good foaming surfactants, which also makes them very suitable for such applications. However, what is desirable in dishwashing detergents can become a challenge during production. This is because the bacteria require air during fermentation. If it is blown through the fermentation liquid, the result would usually be something that Evonik experts ironically call a "foam party". But foam is difficult to control in plants. Evonik's experts have succeeded in solving this problem and transferring the process to an industrial scale.

Rhamnolipids are also already being used in cosmetics. The product called RHEANCE® One won a gold award at the leading trade fair "in-cosmetics international" in Paris. Evonik expert Stefan Liebig also points out the double advantage in the application: "With our rhamnolipids, we give our customers the opportunity to provide consumers with cleaning and care products that are as powerful as they are sustainable."

Due to the very gentle care of the skin, facial cleansers, shampoos or baby care products are possible areas of application. Toothpaste manufacturers are also acquiring a taste for mint. Today, toothpastes are often dominated by the aroma of mint in order to drown out the bitter aroma of the surfactants previously used. "Rhamnolipids are tasteless and are already being used in the first toothpastes, allowing greater flexibility in the formulation," says Lisa Maus.

While these applications still largely revolve around cleaning, rhamnolipids are now also finding their way into markets that sound surprising at first glance. For example, in the paints and coatings market. "They are an excellent wetting agent for color pigments in aqueous formulations," explains Katina Kiep, head of the Decorative Coatings market segment at Evonik, "and thus an environmentally friendly alternative to classic surfactants that enables outstanding color strength. Evonik will offer the product to its customers under the name TEGO® Wet Terra."

In addition to these already available products, Evonik researchers are paving the way for further areas of application. "Many properties of rhamnolipids have been tested in the laboratory and documented in the literature," says Lisa Maus, "we are now investigating whether this also applies to our product and what other undiscovered properties we can make use of." There is interesting potential for use in the pharmaceutical industry, for example. For example, if rhamnolipids make active pharmaceutical ingredients more soluble, this can lead to easier formulation and greater bioavailability.