Surfactants are indispensable as versatile helpers in our everyday lives: these surface-active substances ensure that grease and dirt are dissolved, hair shampoos foam, and oil-water mixtures in creams form stable emulsions. More than 18 million tons of surfactants are synthesized worldwide each year, most of them from fossil raw materials. Manufacturers are increasingly turning to biodegradable plant-based raw materials, but tropical oils such as coconut oil and palm (kernel) oil are primarily used in the production of bio-based surfactants. When these substrates come from crops grown on former rainforest land, this has negative consequences for the climate and biodiversity.

Alternatives are in demand, partly due to the increased demand for ”green“ and sustainable products. ”Some microorganisms form a variety of surface-active substances under natural conditions. These microbial biosurfactants are characterized by a wide range of structures and thus diverse applications, and are also biodegradable,” says Dr. Susanne Zibek from the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB in Stuttgart. For many years, the scientist and her research group have been working on optimizing the biotechnological production of biosurfactants to make them economically competitive.

Promising glycolipid biosurfactants

At Fraunhofer IGB, Zibek is investigating representatives of glycolipid biosurfactants, which consist of a sugar as a hydrophilic head group and one (or more) fatty acid esters as a hydrophobic residue: cellobiose lipids (CL) and mannosylerythritol lipids (MEL). They are produced in large quantities by microorganisms from the Ustilaginaceae family, such as Ustilago or Moesziomyces species.

”We can use renewable substrates such as sugar or regionally available plant oils for production,” says the technical biologist and engineer. In addition to the properties typical of all surfactants, which reduce the surface tension of water, some microbial glycolipids also have antibacterial, antifungal, and antiviral properties, making them ideal for use in cosmetics or plant protection.

Optimized biotechnological production from locally available raw materials and residues

To produce microbial glycolipids, the microorganisms are cultivated in bioreactors and fed with sugar and plant oil as substrates. ”Defined and constant conditions in the bioreactor are crucial for optimal growth of the microorganisms and efficient product formation. Therefore, pH, temperature, and the concentration of oxygen, nutrients and substrates have to be measured and regulated continuously,” explains Zibek.

In numerous national and international research projects and various doctoral theses in cooperation with the Institute of Interfacial Engineering and Plasma Technology (IGVP) at the University of Stuttgart, Zibek and her team have succeeded in characterizing the most suitable production strains and optimizing the entire process control, thereby establishing stable fermentation processes. The researchers were able to improve the cost-effectiveness and reproducibility of the manufacturing process by, for example, replacing an expensive and batch-dependent complex medium with a newly defined mineral salt medium.

Further potential lies in the use of cost-effective substrates, such as those made from locally available raw materials or biogenic residues. ”We can produce our glycolipids using sugars from straw and wood residues, as well as domestic rapeseed oil or insect fat from the insect biorefinery, where fly larvae convert organic waste into fat and proteins,” says Zibek. At the same time, the bioengineer investigated various methods for the efficient separation and purification of biosurfactants and combined them to produce biosurfactants in a highly pure form (> 95 percent purity).

Biosurfactant samples for test formulations and application tests

With improved yields and a robust and scalable fermentation process, the team can now produce glycolipid biosurfactants with defined compositions and corresponding property profiles in reactors with a nominal volume of up to 75 liters. A scale-up to 300 liters is in the planning stage. ”By varying the producer strain, we can also produce different structural variants of the MEL and CL biosurfactants,” explains Zibek. The team currently achieves product concentrations of over 20 grams per liter for CL and up to 50 grams per liter for MEL. ”In addition, we can chemically or enzymatically modify the glycolipids as required – to vary water solubility or emulsifying ability, for example –-and provide support with formulation,” says Zibek.

Fraunhofer IGB is thus opening the door to industry partners who want to test biosurfactants for their specific applications – whether in detergents, household cleaners, as additives in personal care and cosmetic products, or in special applications.

Strategic alliance between research and industry

With the project ”Innovation Alliance for Functionally Optimized Biosurfactants,” the bioengineer initiated an alliance that included partners from research as well as companies from the process engineering and chemical industries. The aim of the consortium was to investigate the entire value chain of biosurfactants: from the suitability of locally available renewable raw materials and residues as substrates, to measurement and control technology for optimizing the fermentation process, to the investigation of properties and application profiles, and a life cycle assessment of biosurfactants. The project was funded in two phases by the German Federal Ministry of Research, Technology, and Space (BMFTR) (www.allianz-biotenside.de/en).

Closing conference of the Biosurfactants Alliance in February 2026

On February 4, 2026, Fraunhofer IGB invites you to the closing conference of the Biosurfactants Alliance in Stuttgart. Here, the renowned partners will present their results from seven years of research for the first time and demonstrate how biosurfactants can be produced in a scalable manner from various raw materials using robust, controllable fermentation and processing methods. Users will present selected use cases – with insights into formulability, performance profiles, and sustainability aspects.