TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The kiln dust comprises one or more of calcium oxide, calcite, anhydrite, sodium, potassium, magnesium or quartz. The kiln dust contains 10-65 mass% of calcium atoms, and at least 15 wt.% of calcium oxide. The catalyst system further comprises a solid acid and/or a molecular sieve; and a fatty acid or its ester. The acid comprises acidic mesoporous aluminum silicate mixed oxide particles.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The (1-5C)alkanol and the (1-5C)alcohol are methanol or ethanol. The surface area of the kiln dust is 0.1-5 m2/g. The molar ratio of (1-5C)alcohol to the glyceride-containing vegetable/animal oil is 600:1-3:1. The fatty acid portion of the glyceride-containing vegetable or animal oil comprises an optionally unsaturated 10-24C alkyl chain, and the 10-24C alkyl chain optionally comprises 1-4 sites of unsaturation, epoxidation and/or hydroxylation. The glyceride-containing animal oil comprises free fatty acids and optionally water. The fatty acid (1-5C) alkyl ester product comprises 50-1000 ppm of calcium atoms. Preferred Method: In the method, the kiln dust is present in at least 0.5 wt.% with respect to the weight of the glyceride-containing vegetable or animal oil. The formation of the vegetable or animal oil-derived, fatty acid (1-5C)alkyl ester is carried out at a temperature of above 40 degrees C, and optionally at a pressure of greater than 1 atmosphere. The kiln dust and (1-5C)alcohol is contacted or heated prior to contact with the vegetable or animal oil-derived fatty acid. The method further comprises: immobilizing the free fatty acids on the solid acid; optionally drying the animal oil by contacting it with the molecular sieve; and optionally separating the molecular sieve and the immobilized free fatty acids from the glyceride-containing animal oil prior to its contact with the kiln dust. In the method, the suspension of kiln dust and methanol comprises 0.1-25 wt.% of kiln dust, with respect to the weight of the dried poultry fat. EXAMPLE - Methanol (180 ml) was added to cement kiln dust catalyst (0.3 g) and the resulting suspension was stirred for 30-40 minutes under refluxing conditions to activate the catalyst thus forming the catalyst system.