Microalgae is now paid attention in view of absorbing carbon dioxide, as well as producing biooil and other potential biomolecules. Phycocyanin (PC) is a kind of phycobiliprotein, and is known as a protein having dye, reported as an application of anti-oxide, anti-inflammable, and other effective chemicals. Phycocyanin has been potential protein in food and medical application. During the leaching from microalgae, several biomacromolecules are included, requiring the selective separation of phycocyanin.
Adsorption has been used for purification of proteins. Adsorbent for protein adsorption has a functional group for protein-adsorption site and pores for mass transfer. Having the large pore in adsorbent improves the higher diffusion coefficient of protein. Pore formation in adsorbent was proposed to enhance the mass transfer by convective flow especially focusing on monolith matrix. Baba et al., prepared the porous material for metal recovery to achieve quick adsorption. Uezu et al prepared porous adsorbent by emulsion polymerization to immobilize surfactant-like compounds at the interface of oil and water phase.
In this study, to adsorb phycocyanin (PC) originated from a microalgae of Nostoc commune, porous spherical adsorbent was prepared by oil-in-water-in-oil emulsion polymerization. Oil and water phases including surfactants and monomers, respectively, were emulsified, adding the prepared emulsion to oil phase, to polymerize porous spherical adsorbent. Concentration ratio of N,N-dimethylacrylamide (DMAEMA), and N,N’-methylenebisacrylamide in water phase was changed. The obtained spherical adsorbent had the mean size of about 150 mm and the water content of 90%, with macro pore at several micrometer. Phycocyanin (20 kDa) of Nostoc commune was leached by freeze and thaw method. Adsorption data of batch and column modes were evaluated by ordinary differential equation and partial differential equation, respectively, in considering competitive adsorption, to obtain the parameters of mass transfer coefficient and saturated adsorption capacity. In batch method, with decreasing DMAEMA ratio the mass transfer coefficient of phycocyanin decreased about one third, but the saturated adsorption capacity increased at three times. In continuous-flow column, leached other biomacromolecules than phycocyanin had higher parameters of mass transfer and capacity. To prepare the adsorbent to the biomacromolecules, adsorption site in polymer matrix should be designed and prepared for selective adsorption. Competitive adsorption sometimes plays important role in separation of bioengineering. This mathematical idea leads to the potential consideration to make continuous separation mode.
Sugimachi, T.; Oshima, T.; Baba, Y. Synthesis of Highly Porous Chitosan Derivative with Phosphinic Acid and Its Adsorption Properties for Rare Metals. J. Chem. Eng. Jpn. 2014, 47, 651-655.
Samatya, S.; Mizuki, H.; Ito, Y.; Kawakita, H.; Uezu, K. The Effect of Polystyrene as a Porogen on the Fluoride Ion Adsorption of Zr(IV) Surface-Immobilized Resin. React. Funct. Polym. 2010, 70, 63-68.