Exploring the activated charcoal adsorption column to improve cosmetic grade C-phycocyanin purification from Spirulina

Abstract

This study investigates the effectiveness of activated charcoal, a common adsorbent, in various packed column configurations in the context of a process to purify C-phycocyanin (C-PC) from Spirulina . The adsorption column performance is considered in isolation and as part of purification trains, which include chitosan treatment and ammonium sulfate precipitation. Operating parameters of interest included activated charcoal particle size, solution retention time in the column and concentration of the Spirulina crude extract used. The feed was a low purity crude extract and the final target was cosmetic grade C-PC (purity > 1.5). A slower column feed flowrate and smaller activated charcoal particle size were shown to improve the degree of C-PC purification via adsorption. Variation of the crude extract concentration did not have a significant effect. In all cases, high C-PC recoveries over the column were achieved. However, use of a single activated charcoal adsorption column was not able to purify the C-PC to cosmetic grade. Cosmetic grade purity (of between 1.68 ± 0.18 and 2.61 ± 0.44) was reached by coupling the column with chitosan treatment and ammonium sulfate precipitation when using a lower feed concentration of 2.60 ± 0.07 mg C-PC mL −1 . A higher concentration feed could not be purified to cosmetic grade within this investigation, confirming that feed concentration affects the efficiency of the activated charcoal column in combination with the other downstream process steps. The overall process had better yields and was able to accommodate a higher concentration of C-PC than reported in literature.

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