Fungal Glycolipids as Biosurfactants
Background: Fungi are key organisms in the biotechnological production of a plethora of products relevant for mankind. Recently several new products from fungi have entered the markets, including biosurfactants. Biosurfactants are microbial produced surface active compounds with emulsifying properties which proved to be an interesting alternative to petrochemically or palm oil derived surfactants. Methods: We have performed a review of the current literature on fungal surfactants and their application, focusing on MEL and CL variants and the microbial strains producing them. We have also included unpublished own findings to further add the newest perspectives for potential application of these biosurfactants. Results: The main fungal biosurfactants currently are generated by species from the order Saccharomycetales and Ustilaginales. These species produce a variety of glycolipids, including sophorolipids, mannosylerythritol lipids and cellobiose lipids. They have been described as promising microbial biosurfactants suitable for personal care, cosmetic, pharmaceutical or biomedical applications as well as in bioremediation technologies like solubilisation and removal of oil from contaminated soil, or in oil recovery. Some of these fungal biosurfactants are already included in cleaning agents and cosmetic products available commercially. The properties of surfactants can be modified by fermentation and feeding strategies as well as by selection of different strains or their genetic modification. By that tailor made surfactants for various applications can be designed. Conclusions: Although fungal surfactants provide a large portfolio of compounds with a performance equal or better than petrochemical derived surfactants and have shown their environmental advantages, commercialization of these molecules remains a challenge due to a higher price at the currently low production volume. More efficient production processes would support further introduction of these compounds into the market. In this review we have given a brief overview and positive resume of the currently available fungal surfactants focusing on MEL and CL, their derivatives and the biotechnological opportunities for their further commercialization.