Oil extraction from microalgae stands as a huge challenge for bioproducts and biofuels production, mainly due to high costs and energy requirement. In this study, maximum cell density, growth curve, lipid content, daily biomass and oil productivities were determined for Chlorella minutissima, Thalassiosira fluviatilis and Thalassiosira pseudonana, strains maintained at the Instituto Oceanografico of the Universidade de Sao Paulo. The microalgal dry biomass was used to evaluate the lipid extraction methodology regarding a sonication bath as pretreatment cell disruption technique followed by vortex mixing and n-hexane as solvent. The results showed a lipid content of 15.5% (% dry weight) for C. minutissima, 40.3% for T fluviatilis and 39.5% for T pseudonana. To determine the feasibility of using microalgae into the biofuel industry is essential to consider the daily biomass and oil productivities along with the lipid content, as could be evidenced in C minutissima. The results indicate that the sonication-assisted method with n-hexane was efficient for lipid extraction in these strains, suggesting a favorable potential for biodiesel production. (C) 2013 Elsevier Ltd. All rights reserved.