Comparative molecular and morphological study on the halotolerant unicellular green alga Dunaliella

Juergen E.W. Polle¹ and E.S. Jin²

¹Department of Biology, Brooklyn College, The City University of New York, Brooklyn, NY; ²KORDI, Research Building 1st 222, SA-dong 1270, ANSAN Kyung Ki Do, Korea

The unicellular green algae of the genus Dunaliella living in saltwater are known to be extreme halotolerant. Some species have been reported to grow even in environmental conditions containing saturated concentrations of NaCl. At the same time described species such as Dunaliella salina and Dunaliella bardawil are used commercially to produce b-carotene. The species D. salina was described by Teodoresco in 1905. The name D. bardawil was given to a new isolate of the genus Dunaliella found in North Sinai in the late 1970’s. Although both species are morphologically very similar the species name D. bardawil persisted to exist in literature. Recent molecular analysis has shown that both species are phylogenetically closely related. However, D. bardawil is still recognized as a separate species. In a combined molecular and morphological approach the species D. salina and D. bardawil have been compared to re-evaluate the current classification of D. bardawil. Our results strongly suggest that D. bardawil is not a separate species but belongs to one subspecies of D. salina.