Dunaliella salina strain selection for beta-carotene production

Seventeen isolates of Dunaliella salina from culture collections and the wild were compared for growth and ability to produce beta-carotene. Several rapidly-growing isolates from the Salton Sea (California) were then used in a program of mutation and selection for constitutive pigment production. Although no strain was found to produce as much beta-carotene in low light as in high light, substantial overall increases in beta-carotene content were observed. All strains showed similar beta-carotene isomer composition. Laboratory photosynthesis measurements and growth studies on a temperature gradient table were used as predictors of outdoor productivity. The increased carotene contents of the cells slowed cell division somewhat, but carotene productivity could be substantially increased in outdoor culture.