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Rudolf Hausmann – green surfactants from bacteria

They share the same name and they both chose an academic career – Rudolf Hausmann, father and son. While Rudolf Hausmann sr. chose to pursue a career in the field of genetics, Rudolf Hausmann jr. found himself drawn to the engineering sciences. What they have in common is their love for biology. In April 2012, Rudolf Hausmann jr. was appointed professor of the newly established chair of bioprocess engineering at the University of Hohenheim. His passion: biosurfactants used in cleaning agents, detergents and foods, which will in the future enable normally non-mixable liquids such as oil and water to be mixed together.

Prof. Rudolf Hausmann at the window of his new office at the University of Hohenheim. © Braitmaier/BioRegioSTERN

“Many people at the University of Hohenheim still remember my father,” said Rudolf Hausmann jr., going on to add, “people often mention him to me.” It’s not clear whether this is an advantage or a disadvantage. Hausmann’s office is still fairly empty: white walls, and furnished in a Spartan fashion with a desk with space for a laptop and a table for visitors – and no more. “I am still in the process of setting up my office and labs,” said Hausmann. In 2013, the multi-use building housing his office will be refurbished, which is why the 42-year-old scientist will delay purchasing office and laboratory equipment for the next few months.

After finishing his chemical engineering studies at the Karlsruhe University of Technology, Hausmann did his doctorate on a classical subject - substance transport coefficients in fluidised beds. However, he was soon attracted by the field of bioprocess engineering, which involves the manufacturing of products such as food, pharmaceuticals, chemicals, etc. from biological materials (produced by microorganisms and plants). Bioprocess engineering closes the gap between technical biology, which focuses on laboratory-scale biological systems, and the classical engineering sciences, which deal with the construction of industrial manufacturing plants. “I am still an engineer and continue to address issues related to classical engineering topics, including the determination of product yields and investigating thermal transport inside manufacturing plants,” Hausmann said. “I’ve always been interested in biology and I attended bioprocess engineering lectures when I was a student,” Hausmann added.

Replacing crude oil and protecting the environment

One of Hausmann’s colleagues at the KIT checking the antifoam device of a bioreactor used for the production of biosurfactants © Baden-Württemberg Stiftung

Bioprocess engineering is a discipline that is gaining in importance and is particularly well represented in Baden-Württemberg. Chemicals such as household cleaning agents, detergents and bioplastics are increasingly produced from renewable materials involving bacteria, enzymes and fungi with the aim of reducing our dependence on dwindling oil reserves. The majority of these substances can be biologically degraded and are also environmentally friendly. Pharmaceutical researchers are also increasingly focusing on drugs produced using biotechnological methods. 

At the Institute of Bioprocess Engineering at the University of Tübingen and subsequently at what is now the Karlsruhe Institute of Technology (KIT), Hausmann cultivated marine sponges, which are of major interest for the pharmaceutical industry due to their ability to supply natural substances. They are also popular models in stem cell research. Research involving sponges has long been neglected as it takes a long time for a marine sponge to grow and produce the desired substances. In addition to sponges, Hausmann also focused on magnetic particles, which can be used as carriers for enzymes or for the industrial-scale purification of bioproducts. 

Hausmann did his habilitation on biologically degradable surfactants, i.e. rhamnolipids produced by Pseudomonas bacteria from the polysaccharide rhamnose and fatty acids. Biosurfactants are used as alternatives to crude oil-based synthetic surfactants, which are the major constituents of washing agents, soaps and household cleaning agents. They consist of a fat-soluble and a water-soluble component. Surfactants diffuse in water as the fat-soluble components enclose dirt and fat particles on clothes and surfaces and the water-soluble groups remain in the water phase. However, at present the industrial manufacturing of biosurfactants is hindered by the high cost of producing them. A kilogramme of biosurfactant costs several hundred euros to produce, while the same quantity of synthetic surfactants only costs around two euros to produce.

Alternative emulsifiers from bacteria

Since Hausmann was appointed professor at the University of Hohenheim, biosurfactants have remained his major topic of research. Hausmann’s department is part of the Institute of Food Science and Biotechnology, which is why he plans to focus specifically on biosurfactants used for food. Natural surfactants such as glycerol lipids and egg lecithin are indispensable as emulsifiers in mayonnaise, yoghurt, mustard, sausages and many other foods. “It would be great to be able to develop alternative emulsifiers, to help us prepare a stable mustard emulsion, for example,” said Hausmann referring to the watery separation that often happens with mustard. “My research will cover all areas related to food bioprocess engineering, from sterile technology to the production of biotechnical products in classical bioreactors and the processing of the desired product,” said Hausmann. The bioprocess engineers are working closely with geneticists and systems biologists with the aim of increasing the yield of a product. The geneticists and systems biologists will be working on the genetic modification of microorganisms and investigate the entire microbial metabolism.

It’s now late in the evening. Hausmann is heading home to Karlsruhe where his 7-year-old daughter is waiting for him. Having to commute between the University of Hohenheim and KIT, where he still continues some of his previous research projects, does not leave him much time for his hobbies, playing the classical guitar and recorder with his daughter. “I’m optimistic enough to believe that a huge effort at first will be worth it in the end. So I am happy to spend extra time travelling,” said Hausmann.

Further information:
Prof. Dr.-Ing. Rudolf Hausmann
Institute of Food Science and Biotechnology/Department of Bioprocess Engineering
University of Hohenheim
Fruwirthstr. 12
70599 Stuttgart
Tel.: +49 (0)711/ 459 - 24 720
E-mail: Rudolf.Hausmann(at)uni-hohenheim.de

Website address: https://www.biooekonomie-bw.de/en/articles/news/rudolf-hausmann-green-surfactants-from-bacteria