Thesis (M.Sc.) - Cairo University - Faculty of Science- Department of Botany Microbiology

Optimum growth and Ýcarotene production of the halotolerant microalga Dunaliella bardawil were recorded at 2.5 M NaCl, pH 7.5 and 2000 Lux whereas the highest glycerol value was obtained at 4 M NaCl. Maximum value of Ýcarotene was recorded at 1.5 M NaCl and 15000 Lux either in presence or absence of solvent. The suitable mixing rate used with solvent was 150 rpm. Milking methods can utilize biocompatible solvent extraction and osmotic shock which cause the migration of the target compound into the harvesting medium without requiring the concentration and killing of cells. In this study, a biotechnological process called "Algal milking" has been established for the continuous production and extraction of secondary metabolites as glycerol and Ýcarotene from Dunaliella bardawil. In long term milking experiments for extraction of a biocompatible solute glycerol, the applied osmotic range was (1.5 to 0.4 M NaCl) and the total productivity of glycerol was 960 and 1050 mg/L when the recovery time was seven and three days respectively and the experiments extended for >49 days. ÝCarotene was extracted in a two phase system with 20 % v/v dodecane at 15000 lux light intensity and 150 rpm mixing rate for two days

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