BACKGROUND: gamma-Valerolactone (GVL) is a high value chemical obtained from hydrogenation of bio-derived levulinic acid (LA). Work to date has focused on batch pressurised catalytic systems where high GVL yield is challenging. In this work, the role of support redox and acidity properties is examined in the continuous gas phase hydrogenation of aqueous LA at ambient pressure over gold on Al2O3, CeO2 and TiO2; Pd/Al2O3 served as a benchmark in catalyst tests. RESULTS: 100% GVL yield was achieved under stoichiometric conditions (inlet H-2/LA = 1) over supported Au (mean size=3.0-4.3 nm). Greater catalytic activity was recorded for Au on reducible TiO2 and CeO2. Under the same reaction conditions, Pd/Al2O3 delivered higher LA consumption rates but promoted formation of pentanoic acid. CONCLUSIONS: GVL formation proceeds via 4-hydroxypentanoic as reactive intermediate. Surface oxygen vacancies (confirmed by O-2 titration) formed during temperature programmed reduction of reducible oxides activate LA for reaction. Greater GVL productivity (with full hydrogen utilisation) is demonstrated in this work relative to state-of-the art supported Pd and Ru catalysts. (C) 2017 Society of Chemical Industry