Abstract: A process for reacting(1) a component selected from the group consisting of sterols and branched aliphatic primary or secondary alcohols having 14 to 32 carbon atoms, and(2) a component selected from the group consisting of fatty acids and fatty acid estersin contact with an enzyme selected from the group consisting of lipase and cholesterol esterase or with the selected enzyme in an immobilized form, in a system selected from the group consisting of an aqueous medium and water-containing organic solvent to prepare a fatty acid ester of the component (1).

Abstract: The present invention provides a process for refining a material lanolin containing pesticides, the process being characterized in that the pesticide remaining in the material is removed by subjecting to at least one step selected from among (1) the step of treating the material in a molten state or in an organic solvent in the presence of a hydrogenation catalyst under the conditions of a temperature of 60.degree. to 210.degree. C., a hydrogen pressure or at least 1 atm. and hydrogen consumption of 0.001 to 0.05 wt. % based on the material lanolin, (2) distilling the material in a vacuum at an absolute pressure of 10.times.10.sup.-3 to 500.times.10.sup.-3 mmHg at a temperature of 150.degree. to 280.degree. C.