Synthesis Of Thermo-responsive Recycling Aqueous Two-phase Systems And Phase Formation Mechanism Analyses With Partition Of ?-polylysine

Aqueous two-phase extraction is a novel bio-separation technology, which was more widely used in many fields for its unique advantages. But the lowest recovery of polymers resulted in the largest cost. In this paper, a recyclable aqueous two-phase systems (ATPS) was constructed by two thermo-responsive copolymers to improve the recovery of two polymers greatly, and the formation mechanism of the ATPS was studied. The application of the ATPS was performed by partition of ?-polylysine.The ATPS was developed by two thermo-responsive copolymers, PvBAm and PN. Copolymer PVBAm was copolymerized using N-vinylcaprolactam, Butyl methacrylate, and Acrylamide as monomers, and PN was synthesized by N-isopropylacrylamide. The lower critical solution temperature (LCST) of PVBAm and PN were 45.0? and 33.5?, respectively. The recoveries of both polymers could achieve 96.6% and 98.3%, respectively. The structures of both copolymers were characterized by infrared equipment, the results were similar to the original ratios of raw materials.The phase behavior and formation mechanism of PVBAm/PN ATPS was studied. Low-field nuclear magnetic resonance (LF-NMR) was applied in the phase-forming mechanism analysis in ATPS. In addition, combining the results of surface tension, transmission electron microscopy and dynamic light scattering, the phase-forming of the PVBAm/PN ATPS was proved.The application was performed by partition of ?-polylysine in ATPS. The results demonstrated that ?-polylysine was extracted into the PN-rich phase and maximal partition coefficient (1/K) of pure ?-polylysine and ?-polylysine fermentation broth was 6.87 and 7.41, respectively. And this method can effectively remove the most impurities from fermentation broth when added the salt (NH4)2SO4 into the ATPS. It is believed that the thermo-responsive recycling ATPS has a good application prospect in the field of bio-separation. The aim of the paper is to build phase system by these two different thermo-response polymers, which could improve the phase-forming ability and partition of products.