Abstract: A glycolipid methyl ester represented by the formula (I), ##STR1## wherein R.sub.3 represents a hydrogen atom or a methyl group, and R.sub.4 represents a saturated or unsaturated hydrocarbon group having 12 to 16 carbon atoms when R.sub.3 is a hydrogen atom, and R.sub.4 represents a saturated or unsaturated hydrocarbon group having 11 to 15 carbon atoms when R.sub.3 is a methyl group, is produced by adding at least one polyhydric alcohol represented by the formula (III) or (IV), ##STR2## wherein R.sub.5 represents a hydrogen atom or a methyl group, R.sub.6 and R.sub.7 represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and m and n represent integers from 1 to 6, to hydrated Sophorolipid, removing water by distillation under reduced pressure, and subjecting the resulting Sophorolipid-polyhydric alcohol system to methanolysis and methylation by reaction with methanol in the presence of a strong acid.

Abstract: A process for producing a glycolipid ester represented by the formula, ##STR1## wherein R.sub.3 represents a hydrogen atom or a methyl group, R.sub.4 represents a saturated or unsaturated hydrocarbon group having 12 to 16 carbon atoms when R.sub.3 is a hydrogen atom, R.sub.4 represents a saturated or unsaturated hydrocarbon group having 11 to 15 carbon atoms when R.sub.3 is a methyl group, and R represents a saturated or unsaturated alkyl group having 2 to 20 carbon atoms, which comprises subjecting Sophorolipid to methanolysis and methylation reactions by reaction with methanol in the presence of a strong acid to produce methyl 1-[(2'-O-.beta.-D-glucopyranosyl-.beta.-D-glucopyranosyl)oxy]-alkanoate and -alkenoate, and subjecting the resulting mixture to ester interchange by reaction with an alcohol represented by the formula,ROHwherein R is the same as defined above.

Abstract: A dehydrating purification process for a fermentation product, which comprises adding at least one polyhydric alcohol represented by the formulae (III) or (IV), ##STR1## wherein R.sub.8 represents a hydrogen atom or a methyl group, R.sub.9 represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and m and n represent integers from 1 to 6, to hydrated Sophorolipid or a secondary derivative thereof which is a fermentation product of Torulopsis bombicola, and distilling off water with heating under reduced pressure.

Abstract: A hydroxyalkyl-etherified glycolipid ester represented by the formula (I), ##STR1## wherein R.sup.1 represents a methyl group or a hydrogen atom, R.sup.2 represents a saturated or unsaturated hydrocarbon group having 11 to 15 carbon atoms when R.sup.1 is a methyl group, R.sup.2 represents a saturated or unsaturated hydrocarbon group having 12 to 16 carbon atoms when R.sup.1 is a hydrogen atom, R.sup.3 represents a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, A represents --CH.sub.2 --CH.sub.2 --O-- or ##STR2## and a,b,c,d,e,f and g represent integers from 1 to 60 in the sum total.