The present invention relates to a method of preparing at least one rhamnolipid comprising: contacting a recombinant cell with a medium containing a carbon source; and culturing the cell under suitable conditions for preparation of the rhamnolipid from the carbon source by the cell, wherein the recombinant cell has been genetically modified such that, compared to the wild-type of the cell, the cell has an increased activity of at least one of the enzymes E1, E2 and E3, wherein the enzyme E1 is an α/β hydrolase, the enzyme E2 is a rhamnosyltransferase I and the enzyme E3 is a rhamnosyl-transferase II, and wherein the carbon source is a C4 molecule.