The algal collection (ACUF) at the Dipartimento di Biologia, Università Federico II of Naples, Italy, is represented by over 600 microalgal strains belonging to Cyanophyta, Chlorophyta, Rhodophyta and Bacillariophyceae. The extremophilic algae (thermo-acidophilic and acidotolerant strains isolated from European and Extraeuropean acidic sites) are widely represented (over 250 strains). Presently, almost all the genera and species of Cyanidiophyceae are maintained in culture. Cultures are available for qualified researchers. As most of the strains are unpublished or still under investigation, the distribution of cultures is regulated in order to avoid conflicts between ongoing research projects.