Sophorolipid lactones produced by Candida bombicola were deacetylated and ring opened with sodium methoxide to their corresponding methyl esters. The methyl esters, after re-acetylation with vinyl acetate using an immobilized lipase, were transesterified with 1,2-3,4-di-O-isopropylidene-D-galactopyranose in tetrahydrofuran using the same lipase catalyst. The di-O-isopropylidene sophorolipid sugar esters were hydrolyzed to give the galactopyranose sophorolipid esters as the final products.