Surfactants and emulsifiers are widely used for food, cosmetic and pharmaceutical applications. Most compounds are still synthesized chemically from hydrocarbons. However, surface-active molecules of biological origin - so called biosurfactants - have gained considerable interest in recent years.
This workshop intends to present the current state of biosurfactants in research and industrial application. International speakers will give overview lectures on topics of interest in the field of biosurfactants to show possibilities, limitations and challenges of this highly interesting class of compounds.
Biosurfactants can be obtained either by chemical syntheses from renewable resources, by microbial fermentation processes or by enzymatic syntheses. They display a wide variety of molecular structures. Their hydrophilic moiety often contains a mono-, oligo- or polysaccharide, an amino acid, peptide or protein, whereas the hydrophobic part is composed of saturated or unsaturated fatty acids, hydroxy fatty acids or fatty alcohols. They can be classified in (i) glycolipids (e.g. rhamnolipids, sophorolipids, trehalose lipids), (ii) lipopeptides (e.g. surfactin, liposan), (iii) phospholipids, (iv) neutral lipids (e.g. corynomycolic acid), (v) polymeric surfactants (e.g. emulsan, liposan) and (vi) particulate biosurfactants (vesicles, whole cells).
The physicochemical properties of many biosurfactants are comparable to chemically synthesized compounds. Advantageously they can be produced from renewable resource substrates or industrial waste products and are on top of that biodegradable. In addition, several biosurfactants have been reported to have manifold biological activities covering antibiotics, fungicides, insecticides, antiviral and antitumoral agents, immunomodulators or specific toxins or enzyme inhibitors, which make them interesting for pharmaceutical applications.
Of special interest for an industrial use are microbial glycolipids: they occur either as an important part of the microbial cell surface enabling the contact with hydrophobic substrates or they are secreted as emulsifiers in the culture broth when grown on water immiscible or oily substrates. Consisting of carbohydrates moieties bond to fatty acid or hydroxy-fatty acid chains they are the main low molecular weight biosurfactant group possessing many commercially attractive properties and clear advantages compared with their synthetic counterparts.
Although the production of microbial biosurfactants has been studied extensively in the last decades, their production on a commercial scale has only been realized in very few cases, and up to now they are only found in niche applications due to their distinctly higher prices compared to traditional surfactants. An interesting option for the future not realized yet could be their use for microbial enhanced oil recovery (MEOR), if it is possible to decrease production costs.