The catalytic pyrolysis of Tetraselmis sp. and Isochrysis sp. was carried out over ceria based catalysts in a fixed bed reactor. There was a clear effect of the catalysts on the product yields and quality, with the catalysts able to recover a large fraction of the starting microalgae energy (67-77%) in the bio-oils. Biooil yield was found to be higher in presence of Ni-Ce/Al2O3 and Ni-C/ZrO2 (26 wt.%). The produced bio-oils had HHVs (higher heating values) of 34-35 MJ/kg and suffered strong deoxygenation, with O level decreased from 40-41% in the starting microalgae to 9-15%. Also, 15-20% N removal was obtained using the ceria based catalysts. The oxygen contents in the bio-oils were remarkably lower than those previously obtained using ZSM-5 (25%) and other species without catalyst (17-24%). H-1 NMR and GC-MS analysis showed that the bio-oils were enriched in aliphatics and depleted in N-compounds and water using the ceria based catalysts. (C) 2016 Elsevier Ltd. All rights reserved.