The response of two strains of Dunaliella, a P-carotene accumulating halotolerant alga, was evaluated under sulphate, nitrate and phosphate limitation. All these factors decreased the growth rate and chlorophyll content but, increased the P-carotene content of the two isolates of Dunaliella, D1, obtained from GTCC and D2 an indigenous strain isolated from Sambhar salt lake, India. Both the strains exhibited accumulation of beta-carotene and glycerol under the different nutrient limiting conditions. A maximum accumulation of 3.99 pg/cell of beta-carotene was observed under phosphate depletion. However, nutrient depletion did not significantly affect the glycerol accumulation in these cells. D2, the indigenous isolate, was found to be a better accumulator of beta-carotene than D1. (C) 2003 Elsevier Science Ltd. All rights reserved.