Biosurfactants

Surfactants are produced worldwide in the order of 18 million tons and are used as detergents, emulsifiers, dispersants and foaming agents in a wide variety of sectors, from the textile industry to mining. Surfactants are synthesized both on the basis of fossil raw materials and from renewable raw materials, such as palm oil, using chemical processes. However, the structural diversity of such chemically produced surfactants is limited and the sustainability of the tropical plant oils used is currently the subject of controversial debate.

Under natural conditions, microorganisms form a large number of surface-active substances, so-called biosurfactants, which cover a broad spectrum of chemical structures. These include glycolipids, lipopeptides, lipoproteins and heteropolysaccharides. The properties of these biosurfactants are comparable or even superior to many synthetic surfactants in terms of surfactant effect and degradability and are therefore of interest for many areas of application in industry.

Our research group is working on the optimization of the biotechnological synthesis of glycolipids, in particular cellobiose lipids (CL) and mannosylerythritol lipids (MEL). They are produced in large quantities by microorganisms from the fungus family (Ustilaginaceae). Their antimicrobial properties also make them interesting for use in clinical and pharmaceutical applications. Using various fungi and different substrates such as mono- and disaccharides, plant oils or residues, customized structural mixtures are to be produced and tested for their application-specific suitability. The objectives here are the characterization and optimization of microbial biosurfactants for use in cleaning agents, cosmetics or for special applications in industry, the use of various renewable raw materials as substrates and the efficient fermentative production of these biosurfactants with the highest possible space-time yields.

• Fermentation and provision of samples of fermentatively produced biosurfactants

• Chemical-enzymatic modification

• Scale-up of fermentation up to max. 10 m3 at the Fraunhofer Center for Chemical-Biotechnological Processes CBP, Leuna

  During process development, we consider all relevant parameters such as temperature, pO2, OUR, CER and RQ or the composition of the medium and establish perfectly matched mineral salt media and feeding strategies (repeated-batch, fed-batch or continuous culture management). Based on a statistical evaluation of all process parameters, we first transfer the optimum process from the shake flask to the fermenter (scale-over) and then to the pilot plant scale (scale-up). The purification of the products is also optimized.