Increased C-phycocyanin Extract Purity by Flocculation of Arthrospira Platensis with Chitosan

This paper demonstrates the possibility of harvesting cyanobacteria Arthrospira platensis at various growth phases followed by the extraction of purer C-phycocyanin from the flocculated biomass, by using chitosan as a flocculating agent. It was found that the flocculation efficiency was higher than 90% in 15 min for the chitosan concentrations of 50 and 100 mg/L, regardless of the growth phase. The C-phycocyanin purity (A620/A280) correlates with chitosan concentration and reaches the values of 1.6-1.9 for the chitosan concentrations of 50 and 100 mg/L with the growth phase dependence. C-phycocyanin extracted from the flocculated (by 50 and 100 mg/L of chitosan) biomass also had enhanced thermal stability as clearly demonstrated by an increase in a residual concentration from 55% to 85-91% when compared with the control after incubation at 60 ?C for 150 min. Nevertheless, antioxidant activity of C-phycocyanin extracts obtained after flocculation processes was 28-37% less compared with the control samples. Thus, the use of chitosan as a flocculating agent for cyanobacteria A. platensis harvesting reduces the time of biomass collecting, increases extracted C-phycocyanin thermal stability and purity (on average, 1.5 times compared with the control), which makes it possible to use it in the food and cosmetic industries, bypassing a purification stage and stabilizing agents addition.