Process integration of foam separation and inverse transition cycling by the thermally responsive properties of ELP-fusion β-glucosidase

The separation and purification technology of enzyme is the key to expand the industrial application of enzymes. However, the traditional separation and purification process with multiple steps, high energy consumption, low efficiency leads to low product yield and large loss of enzyme activity. Herein, a process integration (FS-ITC) of foam separation (FS) and inverse transition cycling (ITC) for separation and purification of the elastin-like polypeptide (ELP)-fusion β-glucosidase based on its thermally responsive properties. The ELP tags realize selective adsorption at the air-liquid interface and temperature-controlled phase separation of recombinant β-glucosidase. As the number of ELP repeats increased, the phase transition temperature of recombinant β-glucosidase decreased, while its surface hydrophobicity enhanced. What is more interesting is that the adsorption rate, foamability and foam stability of recombinant β-glucosidase were significantly improved with the increase of temperature. Separation and purification of recombinant β-glucosidase (Glu-linker-ELP30) from cell lysate by FS-ITC, the enzyme activity recovery and purification fold of recombinant β-glucosidase could reach 95.70 ± 0.67% and 16.28 ± 0.04 under optimum operating conditions. The FS-ITC process integration introduced in this work demonstrated promising potential as a separation and purification process for target proteins with ELP tags.