Effect of light intensity and photoperiod on growth rate and biomass of Chlorella vulgaris

This study provides information on the effect of three light intensities (37.5, 62.5 and lOO!lmol photons.m- 2 s-1) and photoperiods (light:dark) cycle 8:16, 12:12 and 16:8h on growth rate, duplication time and biomass production in microalga Chiarella vulgaris. Stock of C. vulgaris was separated from water samples taken at Anzali Wetland, purified and cultured in lOOOml Erlenmeyer at constant temperature 25±0.5°C, using Zehnder medium.Cell count was conducted daily and biomass was measured at the exponential growth phase in different treatments. Analysis of variance indicated significant difference (P<0.05) among light regimes. The maximum growth rate 1.13d-1 was observed at 10011mol photons.m- 2 s-1 and 16:8h light duration and also the minimum duplication time 0.61d- 1 occurred at this treatment. The maximum biomass 2.05gr 1 was recorded at 62.5!lmol photons.m -2 s-1 and 8:16h light period.