Kinetic models for phycocyanin production by fed-batch cultivation of the Spirulina platensis

Abstract

C-Phycocyanin (CPC) is high-value bioproduct, generated in blue-green algae Spirulina platensis. Its wide application in different industries, widely used in food pharmaceuticals and cosmetics. There are many factors that influence the yields of Spirulina platensis cultivation, such as temperature, light intensity, pH, nutrient etc. Nitrogen is one of the most important factors in cell growth and pigment productivity. The fed-batch process is a strategy to control the growth and enhance CPC accumulation. In this study, Spirulina platensis was cultured in batch and fed-batch modes to investigate the CPC production. Kinetic model of growth and production on nitrate concentration so as CPC accumulation. On batch, cultivation found that increasing nitrogen source concentration led to increased CPC accumulation. The best CPC concentration (2.258 mg·mL-1) occurred when NaNO3 was 3.5 g·L-1. The fed-batch cultivation proved to be an effective strategy to further enhance the CPC production of Spirulina platensis. The results indicate that the maximum CPC production (4.354 g·L-1) and productivity (97.53 mg·L-1·d-1) was obtained when using fed-batch with the NH4HCO3 3.0 mM. A kinetic model to describe the Spirulina platensis culture system including cell growth, CPC formation, as well as nitrogen consumption was proposed. The data fitted the model well. This was in good agreement with the experimental results and could be employed to predict the production of biomass, phycocyanin and the consumption of nitrogen in culture.