Mina Mehdie Shishavan - Department of Biotechnology, Iranian Research Organization for Science and Technology (IROST), Tehran, Iran
Hamideh Ofoghi - Department of Biotechnology, Iranian Research Organization for Science and Technology (IROST), P.O. Box: ۳۳۵۳-۵۱۱۱, Tehran, Iran
Saeid Mirdamadi - Department of Biotechnology, Iranian Research Organization for Science and Technology (IROST), Tehran, Iran

Background and Aim:Microalgae have valuable compounds such as lipids, proteins, polyunsaturated fatty acids, carotenoids, valuable pigments and vitamins that can be used in food, feed, cosmetics, pharmaceuticals industries. Spirulina is an edible (GRAS), photosynthetic and multicellular cyanobacteria (blue-green algae) appertaining to the Oscillatoraceae family. It has several biological activities useful for the body. It has received considerable attention due to its high protein content (50-70%). In order to use proteins, the cell wall has to be break. Spirulina has a relatively fragile cell wall, mainly composed of murein and no cellulose. Many cell disruption techniques to break the cell wall of microalgae such as bead milling, ultrasonication, microwave radiation, enzymatic treatment, cell homogenizer and high-pressure cell disruption have been used.Methods:In this study Spirulina has been grown in Zarrouk medium under conditions 28±2 0C, 2.5 LUX, light/dark cycles 16/8, 120 rpm agitation. Spirulina were harvested by centrifugation during the exponential growth phase. Ultra sonication, bead milling and soaking in distilled water (3, 24, 48, 72 hours) have been investigated to evaluate release of proteins, After centrifugation the supernatant was analyzed for proteins with Lowry method. A calibration curve was prepared using bovine serum albumin.Results:The content of proteins in three cell disruption methods along with a control in distilled water (0 hour) are: 13.7 % control, 63% ultrasonication, 45% bead milling and 41% soaking in D.W. (at different hours did not differ significantly).Conclusion:Therefore Ultrasonication was efficient method to break the cell wall of Spirulina and to release the proteins into the aqueous phase.

Microalgae, Spirulina, ultrasonication, Zarrouk medium