Surfactants are of major importance in our daily life, as they are applied in a multitude of industries, such as the cleaning sector, cosmetic, food and pharmaceutical industry. Over the last century, the surfactant market has become a big business and structural variety increased immensely. However, production of synthetic surfactants, which are petroleum based, has its drawbacks in terms of sustainability, both towards the environment (polluting or energy intensive production process) as in terms of the use of finite fossil resources. Hence, there is a drive to move towards fully biobased alternatives. In the context of a biobased economy, fully biobased surfactants or biosurfactants were developed over the past 20 years and now constitute about 3 % of the surfactant market. These biosurfactants are 100 % derived from biomass and can be produced either through chemical or trough biological synthesis. Within the biological synthesis, so-called microbial biosurfactants are produced by specific species of bacteria, yeasts or fungi. Such microbial biosurfactants constitute a complete new range of molecular structures with promising functionalities, good biodegradability and low ecotoxicity. These microbial biosurfactants are recognised as one of the top bio-based chemicals. Yet, high costs, limited structural variety and relatively low productivities hinder them from fulfilling their market potential. That is why current microbial biosurfactants are only a minor part of the fully biobased surfactant market. 
At Ghent University (InBio.be), huge efforts have already been taken to expand the microbial biosurfactant portfolio through strain engineering of the industrially applied sophorolipid producing yeast Starmerella bombicola and to lower production costs by performing strain engineering and process development and optimization. This project however will focus on another highly interesting type of microbial biosurfactants, so-called branched sophorolipids, resulting in very different properties as compared to the ones produced by S. bombicola. Unfortunately, the production efficiency of these special SLs is only a fraction of the productivity reached for the (commercialised) SLs produced by S. bombicola (typically around 2 g/L/h), which are still considered as very expensive. Thus, currently, the production price of branched sophorolipids is simply too high to be an economically viable alternative to today’s non-sustainable surfactants. This aspect will be tackled within this project through synthetic biology and metabolic engineering driven approaches.