Cao Xuejun

Cao Xuejun

East China University of Science and Technology, China

Title: Recycling aqueous two-phase systems and application in biotechnology



Aqueous two-phase systems (ATPS) were discovered in 1896. Compared with traditional extraction method like organic solvent extraction, ATPS have low interfacial tension and mild operation conditions. Especially, ATPS are suitable for separation of active bioproducts. In the past decades, a key problem is recovery difficulty of polymers forming ATPS. Since 1990s, researchers have focused on development of intelligent polymers forming recycling ATPS and have some essential progress. Our group has synthesized a number of novel copolymers which had high recovery and constructed ATPS. These copolymers include pH–thermo, Thermo-thermo, pH-pH, light-light, light-thermo response intelligent polymers. There are reversible soluble-insoluble polymer and recycled by adjusting pH, temperature or light radiation with 95.0-99.0% recovery at low cost. In this report, above ATPS have been attempted to extract Erythromycin, Lincomycin, Spiramycin, Tea saponin, Stevioside, Demeclocycline, with partition coefficient of 0.0103, 15.89, 12.71, 30.34, 11.54 and 0.084, respectively. These ATPS have also used to bioconversion in synthesis of Cefprozil and Cephalexin with Immobilized Penicillin Acylase, and to degradation of cellulose with soluble complex cellulases cross-linked to a polymer in bottom phase. Products yield have been improved greatly due to reduce and substrates and products inhibition in two phase reactor by adjust partition of substrates and products.
<r> Key words: Recycling Aqueous Two-Phase systems, Extraction, Bioconversion, Antibiotics, Reversible Soluble-Insoluble Polymer