Sustainable hygiene

When brushing our teeth, washing our hands, or doing the dishes, we tend to think that the more foam there is, the more effective the product cleans. “The sooner the foam breaks down, the more often the consumer changes the rinse water,” says Dr. Hans Henning Wenk, Head of Evonik’s research department. “That means the consumer is using additional water, energy, and dishwashing detergent”.

Surfactants are responsible for the cleaning performance and the formation of foam. To date, most surfactants are made with petrochemical raw materials or oleochemical raw materials. Petrochemicals are made of hydrocarbons that are separated and extracted from petroleum (crude oil) and natural gas. Oleochemicals are chemicals derived from vegetable oils in particular tropical oils and animal fats via chemical or enzymatic reactions.

Together with the consumer goods group Unilever, Evonik has developed a novel surfactant based on substances called rhamnolipids. Rhamnolipids don’t only foam well, they remove dirt just as well as the best surfactants on the market. In addition they are gentle to the skin, much better tolerated by aquatic organisms and are completely biodegradable. The latter is very important for emerging economies where wastewater is not processed as intensely as in industrialised countries. 

The starting point for the development of the bio surfactant was the bacterium pseudomonas aeruginosa, which lives in nature in soils and produces rhamnolipids from fats – but only in very small quantities. It is also pathogenic and therefore unsuitable for industrial use. Evonik decided that sugar should serve as the basis of the process, because it is available everywhere from regional sources that are not competing with sensitive ecosystems. The rhamnolipids are now produced by a strain of bacteria from the Pseudomonas putida family that is already used in other industrial applications. The strain was bred to have the ability of the original bacterium to produce rhamnolipids.