Comparison of growth rate and protein content by Spirulina Platensis in Photobioreactor and Shake Flask

BACKGROUND AND OBJECTIVESSpirulina is known for its high nutritional value and potential industrial applications. The influence of cultivation conditions on the growth of the cyanobacterium Spirulina platensis was investigated by using two types of methods, bubble column photobioreactors, and shaker Erlenmeyer flasks, to compare growth performance, biomass productivity, and protein content.MATERIALS AND METHODSCultures were grown in Zarrouk's medium and exposed to a range of light intensities (۳۰۰۰ LUX), with a light/dark cycle of ۱۶/۸ h. at room temperature, pH ۹.۵, Providing aeration for the photobioreactor with a central bubble column in which the intensity of aeration and mixing was set at ۱۰۰۰ ml/min ۸-hour intermittent aeration during ۲۴ hours. and flask aeration was provided by the digital shaker which was adjusted for ۲ hours stirring and ۲ hours resting continually to provide sufficient aeration and mixing. bubble column photobioreactors and Erlenmeyer flask compared for their performances during the cultivation of Spirulina platensis. Culture conditions were kept the same and different parameters were examined through the experiments.RESULTS AND DISCUSSIONThe results showed that the photobioreactor yielded significantly higher biomass concentration and growth rate. After ۱۲ days, the bioreactor achieved ۳.۲۷ g/L of biomass while the flasks only reached ۲.۱۲ g/L, Subsequently, on the ۵th day, the growth in the photobioreactor was ۱۰% higher than the flask and continued to the ۸th day, after that this difference decreased. In Protein analysis the highest amount of protein in both environments was estimated on the ۱۰th day of cultivation in terms of biochemical composition, the photobioreactors produced Spirulina with higher protein (۵۵-۶۰% vs ۴۰-۴۵%) levels compared to the shake flasks.CONCLUSIONThe higher yields in the photobioreactors are attributed to better light penetration and distribution, as well as improved mixing and mass transfer. In the shake flasks, much of the light is absorbed or reflected in the liquid-air interface rather than penetrating the culture. Ultimately, the choice between a photobioreactor and an Erlenmeyer flask depends on the specific requirements and goals of the Spirulina cultivation.

کلیدواژه ها:

Photobioreactors ، Growth rate ، Spirulina ، Erlenmeyer flask ، Protein content