One-step purification of glutamate decarboxylase from E. coli using aqueous two-phase system

The aqueous two-phase system (ATPS), formed when two polymers or one polymer and one salt are mixed together at appropriate concentrations, is a clean technique to separate and purify biomolecules. ATPS has many advantages over traditional downstream process, especially on the integration of concentration, extraction, and partial purification if properly optimized, which reduce multiple processing steps involved hence in improving the yields and costs of the recovery process. Here, we describe an integrated purification process of glutamate decarboxylase (GAD) from E. coli cell extract using the established ATPS that consists of polyethylene glycol (PEG) and sodium sulfate.