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Objective: New Strategy for solubilization and refolding of recombinant human Interferon α2b inclusion bodies was established to obtain a high solubilization and refolding rate of recombinant human Interferon α2b inclusion bodies from E. coli Gene Overexpression System.Method: The IFN-α2b inclusion bodies were solubilized with solubilizing buffer of 2mol/L urea. Refolding was performed via two steps, diluting by pulse adding the solubilized IFN α2b sample and dialysing it slowly using ultrafiltration 5K step by step. Finally refolded IFN α2b was purified through Cu 2+ chelate affinity chromatography. Results: The urea concentration of 2mol/L in the solubilizing buffer gave the solubilization rate of 89.73%. Diluting the solubilized IFN α2b sample by pulse adding gave the refolding rate of 78.53%. The multi steps dialysis through ultrafiltration membrane 5K gave the antiviral activity recovery of 98.73%. The purification through one step Cu 2+ chelate affinity chromatography raised the specific activity of IFN sample to 1.4×10 8 U/mg protein and 12% SDS-PAGE showed single band of purified IFN-α2b at expected MW height, whose purity was 99.8%. Conclusion: Large-scale production of recombinant human Interferon α2b (IFN-α2b) in E. coli with a thermoinducible overexpression system was established by applying an effective solubilizing and refolding processes of interferon α2b inclusion bodies (IBs). Solubilization and refolding rate of IFN-α2b IBs were 89.71% and 79.87% respectively. Refolded IFN-α2b was purified through one-step immobilized metal affinity chromatography to give a pure bioactive IFN-α2b with the specific activity of 1.4×10 8 IU/mg protein and with the recovery rate over 52.89%.

In this paper, we propose an approach to tune optimal parameters of a robust PID controller by means of computed torque control (CTC) strategy for trajectory tracking of a Delta parallel robot, using a hybrid optimization algorithm of Particle Swarm Optimization (PSO) and differential evolution (DE). It differs from previous works that they propose robust PID controller parameters tuning based on conventional gradient-based optimization algorithms and apply them to process control. First, we reduce the tuning problem of a robust PID controller with CTC strategy satisfying requirements including robustness and disturbance attenuation to an optimization problem with nonlinear constraints by considering the nonlinear dynamic model of a Delta parallel robot. Second, we set up the design characteristics for the trajectory tracking of a Delta parallel robot. Then, we propose a robust PID controller in a way of obtaining the global optimization solution of the nonlinear optimization problem by running a PSO-DE hybrid optimization algorithm of finding the global optimal solution by maintaining the diversity of swarm during evolution based on the evolution of cognitive experience. Simulation and experimental results demonstrate that the proposed controller outperforms previous works with respect to robust performance and active disturbance attenuation when it is applied to tracking control of a Delta parallel robot.

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