Abstract: The present invention relates to the field of production of novel biosurfactants. More specifically, the present invention relates to the efficient generation of short chained on-glycosides with less than 10%, preferably less than 1%, ?-1 glycosides using a fungal strain such as the yeast Starmerella bombicola having a dysfunctional CYP52M1 cytochrome P450 monooxygenase and a dysfunctional FAO1 fatty alcohol oxidase to produce high amounts of so-called unsaturated (symmetrical) ?,?-bola glycosides free from contaminating ?,?-1 bola glycosides, and subjecting said unsaturated (symmetrical) ?,?-bola glycosides to conditions inducing the breaking of the present double bond(s) such as for example through ozonolysis performed in water. More specifically, the present invention discloses the generation of (acetylated) C9:0 ?-sophoroside aldehydes, C9:0 ?-glucoside aldehydes, C9:0 ?-glucolipids, C9:0 ?-sophorolipids, C9:0 ?-sophoroside alcohols and C9:0 ?-glucoside alcohols and their further derivatives.