Abstract: The present invention relates to the field of microbial production of novel biosurfactants. More specifically, the present invention discloses the usage of a fungal strain such as the yeast Starmerella bombicola having a dysfunctional CYP52M1 cytochrome P450 monooxygenase and a dysfunctional FAO1 fatty alcohol oxidase for producing high amounts of so-called “symmetrical bolaform sophorosides” where both sophorose moieties are attached through a terminal glycosidic linkage to the hydrophobic linker. In addition, the present invention further discloses that the latter yeast can also be used to produce alkyl sophorosides and symmetrical bolaform glucosides.