In order to contribute for a more sustainable biodiesel production, its synthesis from animal fat through heterogeneous catalysis was studied, by focusing on: (i) selecting a heterogeneous catalyst for pork lard transesterification; (ii) studying the influence of the reaction conditions on biodiesel purity, namely by using response surface methodology (RSM); and, (iii) evaluating the re-use of the catalyst. Calcium manganese oxide was the selected heterogeneous catalyst for the transesterification of lard obtained from a meat processing industry. RSM studies allowed the development of a second-order model representing the influence of the reaction conditions on biodiesel purity; the temperature and the combined effect of the temperature and catalyst concentration were the conditions which mostly influenced product purity. Catalyst was reused without significant loss of activity indicating that catalytic behaviour was heterogeneous. (C) 2011 Elsevier Ltd. All rights reserved.