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Full list of author information is available at the end of the articleas well as active pharmaceutical ingredients [1-5]. Microal-gae have exclusive advantages over higher plants for the sustainable production of both valuable compounds and biomass, since they do not compete with agricultural crops for land. D. salina is a model species of green microalgae which has been widely cultivated outdoors for β-carotene under environmental stress conditions in contrast to the original Dunaliella strain (UTEX LB #200). Lutein has been widely used as a feed additive and a food coloration agent in industry [8] and it may also protect against age-related macular degeneration in humans [8,9]. Lutein demand in the global market has been increasing rapidly in recent years [8,10]. At present, lutein is mainly produced from the flowers of marigold, but the content is low, 0.3 * Correspondence: weiqi@hi.isPhotosynthetic microalgae have recently been exploited forBackground: Recent years have witnessed a rising trend in exploring microalgae for valuable carotenoid product