Dunaliella salina is a unicellular microalgae that can be used as aquatic feed since contain protein and carotenoid. Commercialization of this microalgae requires extensive efforts on cost reduction. This can be achieved by minimization of nutrient cost and maximization of growth rate and productivity. Hence, in this study, mixotrophic cultivation of D. salina on pure and crude glycerol (by product of fatty acid calcium salt process) was investigated. Due to the high cost of organic carbon sources such as glucose, fructose, ethanol and acetate, using cheap resources is one of the ways to economize cultivation of microalgae. Photobioreactors can significantly increase the production efficiency. Among various types of photobioreactor, helical photobioreactors are more appropriate in terms of cost of construction, maintenance costs and scalability. In this study, the influences on protein, carotenoid and chlorophyll content were studied. The results showed that maximum specific growth rate and protein and carotenoid productivity attained at the cultivations on 2.5 g/l crude glycerol and 5 g/l pure glycerol. Then, D. salina was cultivated in continuous mode in a helical photobioreactor using inlet flow of 3.1 L.day -1 (dilution rate of 0.5 day -1 ) containing 2.5 g/l crude glycerol. The productivity of biomass and protein there were calculated as 4229.3 ?g protein.L -1 .day -1 and 300 ?g carotenoid.L -1 .day -1 . Therefore, the cultivation of D. salina on crude glycerol (2.5 g/l) in a helical photobioreactor in continuous mode was proposed as a potential process technology for production of D. salina in large scale. Protein wastes is another product from poultry and livestock industry that can be used as a nitrogen source by processing them. Crude glycerol provides a cheaper carbon source and if a low-cost nitrogen source is substitute for pure nitrogen, it will make the process more economical. The animal waste tissues are sources of organic nitrogen. They were hydrolyzed with soudium hydroxide in this study and were mixed with the culture. The highest cell growth was observed at 2.5% volumetric concentration of haydrolysate. The cell growth rate was sharply reduced at hydrolysate concentration of above of 5%. Keywords: Dunaliella salina , crude glycerol, mixotrophic cultivation, organic nitrogen, haydrolysate
