Development of a three-zone simulated moving bed process based on partial-discard strategy for continuous separation of valine from isoleucine with high purity, high yield, and high product concentration

• The optimal SMB for continuous separation of valine from isoleucine was developed.
• The SMB consisted of three zones that were packed with Amberchrom-CG161C adsorbent.
• It was optimized to maximize throughput while maintaining purity and yield ≥98%.
• Partial-discard strategy was then applied to increase valine product concentration.
• The optimized SMB with the partial-discard strategy was validated experimentally.

The issue of separating valine from isoleucine has been a major concern in the biotechnological process for production of valine. To address this issue, an optimal three-zone simulated moving bed (SMB) process for continuous separation of valine was developed in this study. It was first found that an Amberchrom-CG161C resin was highly suitable for the adsorbent of such SMB process. The adsorption isotherm and mass-transfer parameters of valine and isoleucine on the Amberchrom-CG161C adsorbent were then determined through multiple frontal experiments. The determined parameters were used in the next stage of optimizing the SMB for valine separation, which was performed on the basis of genetic algorithm. For the optimized SMB process, a partial-discard strategy was applied to the raffinate port in order to make a further improvement in the valine product concentration. Finally, the optimized SMB based on the partial-discard strategy was tested experimentally using the self-assembled SMB equipment. The experimental results showed that the developed process in this study was highly effective in continuous separation of valine from isoleucine while ensuring the attainment of high product concentration. The experimental data for the SMB effluent histories and the SMB column profiles were also in close agreement with the model predictions.