Developing an economical algae harvesting system still remains a challenge today. One of the strategies to decrease harvesting costs prior conversion is employing technologies that can have additional benefits apart of separation. In this work we explore ozoflotation as a technique to recover microalgae grown in treated wastewater and we evaluate the effect of ozone on lipid and FAME recoveries. A high percentage of biomass can be harvested (79.6% as TSS) when using an ozone dose of 0.23 mg/mg of dried biomass. Additionally, two interesting effects of ozone were found in this study. The amount of lipid extracted and FAME recovered from the biomass, at least, doubles when using ozoflotation (with ozone doses of 0.12-0.23 mg/mg of dried biomass) than when using centrifugation. And, the oxidative stability of biodiesel can be enhanced by the effect that ozone has in the degree of FAME saturation. (C) 2014 Elsevier Ltd. All rights reserved.