The microbial degradation of aromatic pollutants has been well characterized over a period of more than 30 years. The microbes of most interest have been bacteria and fungi. Only relatively recently has the question of how algae figure in the catabolism of these compounds attracted a degree of interest. The aim of this review is to highlight the biodegradative capabilities of microalgae on aromatic compounds, ranging from simple monocyclic to more complex polycyclic pollutants. This paper will briefly encompass studies which have investigated the growth on and the oxidation of these compounds by algae, as well as a more derailed characterization of the catabolic sequences involved in the transformation of these compounds. (C) 1999 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.