In this work, it was shown that glycerol (Gly) can be effectively converted to lactic acid (LA) under inert atmosphere using a Pt/ZrO2 catalyst. Starting from pure glycerol, at 180 degrees C and under a He pressure of 30 bar, we were able to achieve up to 80% yield of LA after a reaction time of 8 h. The catalysts performance of Pt/TiO2, Pt/C and Pt/ZrO2 were compared showing that using Pt/ZrO2 high conversion and stable LA selectivity were achieved during all the process. Further, using Pt/ZrO2 the LA selectivity was less sensitive to the nature of the reaction atmosphere while using either H-2 or He. While using crude Gly (85% purity), a lower reaction rate was obtained in the presence of Pt/ZrO2, however high selectivity to LA (similar to 80%) was maintained. (C) 2014 Elsevier B.V. All rights reserved.