Continuous protein crystallisation platform and process: Case of lysozyme

In this work, we designed and built a continuous crystallisation oscillatory flow platform. The lysozyme crystallisation behaviours were investigated at concentrations from 30 to 100 mg/mL, under oscillatory conditions with amplitude (x0) from 10 to 25 mm and frequency (f) from 0.05 to 0.25 Hz in a batch oscillatory flow crystallisation platform. The nucleation rate increased with increase in concentration of initial lysozyme solution, and was also found to increase with increase in shear rate. By learning the thermodynamics and kinetics of lysozyme crystallisation in batch oscillatory flow, the batch crystallisation process was successfully transferred to a continuous oscillatory flow crystallisation process. The equilibrium state of continuous crystallisation reached at residence time 200 min, and the final product crystals shape and size were consistent during the continuous process. This work demonstrates the feasibility of oscillatory flow based platforms for the development of continuous protein crystallisation as for downstream bioseparation.