1：Experimental Design and Method Selection:

The study involved the use of ATPSs comprising N,N-dimethylammonium N′,N′-dimethylcarbamate (DIMCARB) and thermo-responsive poly(propylene) glycol (PPG) for the recovery of GFP. The partition behavior of GFP was investigated by varying the molecular weight of PPG and the total composition of ATPS.

2：Sample Selection and Data Sources:

Recombinant GFP was derived from Escherichia coli. The GFP was expressed by E. coli strain BL21(DE3)pLysS transformed with pET28a-GFP plasmid.

3：List of Experimental Equipment and Materials:

Materials included DIMCARB, PPG, Tris base, Luria-Bertani (LB) broth, kanamycin sulfate, chloramphenicol, ethanol, isopropyl β-D-1-thiogalactopyranoside (IPTG), methanol, acetic acid, Coomassie Brilliant Blue R-250 (CBB-R250) staining solution, and protein marker. Equipment included an ultrasonic homogenizer, spectrofluorometer, SDS-PAGE electrophoresis unit, and gel imaging system.

4：Experimental Procedures and Operational Workflow:

The GFP was expressed, harvested, and disrupted. The partitioning of GFP in ATPSs was investigated, and the compositions of the phase-forming components were selected based on the corresponding phase diagrams. The GFP concentration was determined spectrofluorometrically, and protein quantification was performed.

5：Data Analysis Methods:

The partition coefficient of GFP and total protein was determined, and selectivity and yield were calculated. SDS-PAGE analysis was performed to assess the purity of protein.