Optimization Of Culture Conditions For D. Salina, Selection Of Productive Strains And Analysis Of RDNA ITS And RbcL Sequence Variations Among Different Strains

In this paper, monocolony isolation and ultraviolet radiation mutagenesis are used to select productive strains of Dunaliella salina which grows fast and is good at accumulatingβ-carotene. The optimization of culture conditions for D. salina including light, temperature and nutrition is carried out in and out of lab. Thus, the basal experimental and theoretic studies can be provided for regulating ecological factors on-line in mass culture process. Moreover, the rDNA internal transcribed spacer (ITS) region and rbcL gene sequences of 8 strains of Dunaliella including four selected strains (D. salina BJ38, OUC21, OUC36 and OUC66), two culturing strains (D. salina Inner-mongolia and Israel), D. primolecta and D. sp. hd10 are cloned. Systematic and genotypic variation analysis among the 8 strains are performed based on the two sequences.Two strains are selected using monocolony isolation method, namely D. salina BJ8 and BJ38. In order to find out the best suitable condition of light intensity, temperature and concentration of nutrition for the growth andβ-carotene accumulation of D. salina, the effect of them on growth andβ-carotene accumulation of D. salina is carried out. The two selected strains (BJ8 and BJ38) and the initial strain (D. salina BJ) are compared using Orthogonal Design. As a result, the best light intensity and temperature conditions for algae growth are 145.3μmol?m-2?s-1 and 23℃respectively, while the light intensity of 218.2μmol?m-2?s-1 and the temperature of 23℃induces the mostβ-carotene accumulation. The NaNO3, CO(NH2)2 and NaHCO3 concentrations are 0.4 , 0.6 and 18 mmol/L for the highest growth and 0, 0.2 and 18 mmol/L respectively forβ-carotene accumulation. Results further reviews that high light intensity ( 218.2μmol?m-2?s-1) and low temperature (15℃) induce moreβ-carotene accumulation of D.