Synthesis of two thermo-responsive copolymers forming recyclable aqueous two-phase systems and its application in cefprozil partition

Aqueous two-phase systems are efficient purification methods for bioproducts. However, recovery difficulty of the copolymers forming aqueous two-phase systems becomes obstacle in scale-up application. In the study, novel recyclable aqueous two-phase systems have been developed by using two thermo-responsive copolymers, PNE and PVAm. Copolymer PNE was copolymerized by using N-isopropylacrylamide and ethyl methacrylate as monomers, and PVAm was synthesized by using N-vinylcaprolactam and acrylamide as monomers. The lower critical solution temperatures of PNE and PVAm are 28.7 °C and 35.6 °C, respectively. The recoveries of both polymers can reach over 95%. The minimal and maximal partition coefficient of cefprozil was 0.33 at 50 mM NH4F and 6.55 at 70 mM LiCl. Two empirical equations were used to correlate with experimental binodal curve. Partition coefficients of cefprozil examined in the ATPS were correlated with tie-line length and calculated partition coefficient.