The present study is focused on purification, characterization and comparison of phycoerythrins from three different marine cyanobacterial cultures - Phormidium sp. A27DM, Lyngbya sp. A09DM and Halomicronema sp. A32DM. 'Phycoerythrin' was successfully purified and characterized. On SOS-PAGE, the PE purified from all three young cultures showed four bands - corresponding to alpha and beta subunits of each of PE-I and PE-II. However, phycoerythrin purified after prolonged growth of Phormidium sp. A270M and Halomicronema sp. A32DM showed only one band corresponding to 14 kDa whereas Lyngbya sp. A09DM continued to produce uncleaved phycoerythrin. The absorption spectra of purified PEs from all the three young and old cultures showed variations however the fluorescence studies of the purified PEs in all cases gave the emission spectra at around 580 nm. The described work is of great importance to understand the role of phycoerythrin in adapting cyanobacteria to stress conditions. (C) 2010 Elsevier Ltd. All rights reserved.