Primary recovery of recombinant human serum albumin from transgenic Oryza sativa with a single-step aqueous biphasic system

Abstract

Recent advances in genetic engineering technology have provided various methods in recombinant proteins production for pharmaceutical purposes. However, the development of the effective purification strategy remains the major challenge for large-scale production of therapeutic proteins because high purity of the proteins is often demanded. In this study, recombinant Oryza sativa L. cv Tainung 67 human serum albumin (OsrHSA) was expressed and purified with a single-step polyethylene glycol (PEG)/phosphate aqueous biphasic system (ABS). The optimum condition of PEG/phosphate ABS for the purification of OsrHSA was determined by investigating the effects of PEG molecular weight; pH; tie-line length (TLL); and volume ratio (VR) of ABS on the OsrHSA purification efficiency. The purification efficiency of OsrHSA was evaluated based on the partition coefficient (KHSA) and recovery yield (RB) of the OsrHSA in the PEG/phosphate ABS. An RB of 69.8% of OsrHSA was recovered in the optimum PEG/phosphate ABS consists of TLL of 26.0% (w/w) of pH 7.5. In addition, large-scale ABS were attempted and results showed that the recovery efficiency of 3000 g ABS was consistent with a 10 g ABS. This novel finding has demonstrated that the feasibility of ABS as a potential tool to purify HSA protein in one-step operation.