BACKGROUND: Hydrodeoxygenation (HDO) of Chlorella algal oil extracted with supercritical hexane and stearic acid as a model compound was investigated over several supported Ni and Mo2N-MoO2 catalysts in a semibatch reactor at 300 degrees C under 30 bar in the presence of hydrogen. RESULTS: The results showed that all catalysts were very active in HDO of stearic acid. With crude algal oil, a maximum conversion of lipids of 35% was found with an acidic Ni-HY-80 zeolite catalyst after 360 min. The main products in algal oil HDO were fatty acids; whereas maximally only 7% hydrocarbons were formed with Ni-HY-80. The main hydrocarbon products were formed via decarbonylation, as the hydrogenation/dehydration route was suppressed. CONCLUSIONS: Hydrodeoxygenation of crude Chlorella algal oil was demonstrated over nickel supported on beta zeolite and with a molybdenum oxide-nitride catalyst. Strong catalyst deactivation occurred for the former catalyst, whereas the latter retained its activity. (C) 2016 Society of Chemical Industry