Turk. J. Fish.& Aquat. Sci. 19(5), 399-407 http://doi.org/10.4194/1303-2712-v19_5_05 Publishedby Central FisheriesResearchInstitute (SUMAE) Trabzon, Turkey in cooperation with Japan International CooperationAgency (JICA), Japan R E S E A R C H P A P E R Isolation, Molecular Identification and the Carotenogenesis Process of the Microalgae Dunaliella salina Strain DunaDZ1 Isolated from an Algerian Salt Lake Hafsa Yaiche Achour 1, * , Amel Doumandji 2 , Noureddine Bouras 3,4 , Nasserdine Sabaou 4 , Patricia Assunҫão 5 1 Laboratoire de Recherche de Biotechnologiedes Productions Végétales, Biotechnology Department, Life Science Faculty, Blida 1 University, BP 270, 09000, Blida, Algeria. 2 Laboratoire de Recherche de Biotechnologie des Productions Végétales, Agri-Food Department, Life Science Faculty, Blida 1 University, BP 270, 9000, Blida, Algeria. 3 Département de Biologie, Facultédes Sciences de la Nature et de la Vie et Sciences de la Terre, Université de Ghardaïa, 47000, Ghardaïa, Algeria. 4 Laboratoire de Biologie des Systèmes Microbiens (LBSM), Ecole Normale Supérieure de Kouba, Alger, Algeria. 5 Instituto Tecnológico de Canarias (ITC), Departamento de Biotecnología, División de Investigación y Desarrollo Tecnológico, Pozo Izquierdo, 35119, Sta. Lucía, Canary Islands, Spain. Article History Received 11 January 2018 Accepted 07 May 2018 First Online 15 May 2018 Corresponding Author Tel.:+213.777 373413 E-mail: hafsa_yah@hotmail.fr Keywords Dunaliella Taxonomy ITS rbcL Carotenoids Abstract Algeria has a high algal biodiversity, which is of great interest and should be exploited. Isolation of Dunaliella strain DunaDz1 from Sidi Ameur Lake in Algeria was carried out in this study. The aim of this research was to identify the isolated strain by morphological and molecular taxonomy using ITS and rbcL genes. The effect of two stress factors, salinity and nitrate starvation on the carotenoids accumulation in Dunaliella strain was investigated on f/2 and Johnson media. The results for both genes showed that strain DunaDz1 is part of a clade containing several strains of D. salina. The strain grew well in Johnson medium, with a cell number of 56.09 10 5 cell/ml and a chlorophyll a amount of 63.63 µg/ml. Salt stress lead to a noticeable increase in the total carotenoids levels of strain DunaDz1, 23.68 ± 0.12 and 23.15 ± 0.23 pg/cell, for f/2 and Johnson media, respectively. In nitrate starved media a lesser amount was recorded comparing with salt stress: 11.42 ± 0.22 and 16.2 ± 0.24 pg/cell, for f/2 and Johnson media, respectively. The combination of these two factors was more effective on f/2 medium than Johnson medium. Introduction Dunaliella is a unicellular, eukaryotic and halo- tolerant microalgae. This genus is grouped in the class Chlorophyceae, the order Dunaliellales and the family Dunaliellaceae. Cells are motile with two flagella. The main morphological characteristic of the Dunaliella genus is the lack of a rigid wall (Shariati & Hadi, 2011). Molecular taxonomy is an advanced and reliable method for the characterization and differentiation of morphological plastic organisms (Preetha, John, Subin, & Vijayan, 2012; Olmos Soto, 2015). Identification of Dunaliella species/strains has already been the subject of morphological, physiological and molecular studies (Hexin et al., 2016; Kim, Ahn, Jeon, & Jin, 2017; Shaker, Morowvat, & Ghasemi, 2017). Internal Transcribed Spacer (ITS) regions have been frequently utilized for discrimination of genetic variation in green algae and to study the phylogeny and taxonomy of Dunaliella, as well as the ribulose-bisphosphate carboxylase (rbcL) gene (Coleman, Suarez, & Goff, 1994; González, Coleman, Gómez, & Montoya, 2001; Buchheim, Kirkwood, Buchheim, Verghese, & Henley, 2010). The ITS region is one of the more frequently utilized regions at the genus and species levels (Hejazi, Barzegari, Gharajeh, & Hejazi, 2010; Preetha et al., 2012). However, the main difficulty of performing phylogenetic analyses of the genus Dunaliella is the misinformation available at culture collections and GenBank regarding the identification of strains and sequences. The taxonomy of the whole genus Dunaliella should be re-examined (Assuncao et al., 2012). Dunaliella salina (Dunal) Teodor. is known as a