Morphological, Physiological, and Biochemical Characteristics of the Sarcinoid Microalga Chlorosarcinopsis eremi (Chlorophyceae, Chlorophyta)

The strain VKM Al-132 of green sarcinoid microalgae isolated from chestnut soil of the dry steppe zone (Volgograd oblast of Russia) was investigated. With the help of light- and scanning electron microscopy, together with the molecular phylogenetic analysis of the 18S rRNA gene and the ITS2 spacer, the strain was identified as Chlorosarcinopsis eremi. The characteristics of its growth and secondary carotenogenesis were examined under conditions of two-stage batch culture. After 21-day cultivation, the average productivity was 0.12 g/(L day) (dry biomass) and 0.2 mg/(L day) (total carotenoids). At the end of the stage of secondary carotenogenesis, when the percentage of total carotenoids was approximately 0.25% of dry biomass, canthaxanthin and diesters of astaxanthin fractions dominated; the sum of astaxanthin esters attained 36% of total carotenoids. It has been shown that the VKM Al-132 strain of C. eremi may serve as a potentially perspective object to search for optimal conditions for intensification of carotenoid biosynthesis.