Optimization of culture conditions of an Argentine strain of Dunaliella salina (Chlorophyta), for the synthesis of beta-carotene

Dunaliella salina is a green microalga, which synthesises and stores large amounts of beta-carotene under certain environmental conditions. For this r eason it is grown massively for commercial purposes in several countries. T he aim of this study was to find the optimal conditions for growth in labor atory of an Argentine strain of D. salina, for the synthesis of beta-carote ne. The samples were isolated and grown in two culture media: modified John son and ASP-H. Four concentrations of ClNa (0M, 1.5M, 3M and 4.5M) were use d with a pH of 7-7.5, at 30-36 degrees C and continuous light, under a phot on flux of 290 mu E m(-2) s(-1). Cell density was obtained by successive co unts in a Newbahuer chamber. Growth rate(K) and doubling-time (Td) during t he exponential were determined in each case. The cultures of the low concen trations presented an increase in cell density with a greater differentiati on of phases than the cultures of high concentrations. D. salina tolerated wide concentration ranges of ClNa under laboratory conditions, synthesizing beta-carotene in concentrations of 4.5M and 3M, one month and three months after the culture was started, respectively.