The use of reflector film in a cyanobacteria culture rack provides a good light intensity. The effect of light intensity on Spirulina platensis biomass, phycobiliprotein and amino acid content using KNO3 and urea as a nitrogen sources were studied. Maximum biomass productivity 6.9 mg ml(-1) and 6.1 mg ml(-1) with light reflector (LR) + urea and LR + KNO3 respectively, were noticed. The C-phycocyanin (148.1 +/- 2.2 mg g(-1)) and allophycocyanin (45.2 +/- 0.94 mg g(-1)) contents were reached maximum at 4 klx. The rack system with reflector gave good effect of light intensity (4.8-6.0 klx) than the normal system (2-3 klx). Results showed that reflector used cultivation improved biomass, proteinic pigments and protein biosynthesis in S. platensis. This method of cultivation is simple, inexpensive and requires low energy. (C) 2012 Elsevier Ltd. All rights reserved.