Continuous-mode separation of fucose and 2,3-butanediol using a three-zone simulated moving bed process and its performance improvement by using partial extract-collection, partial extract-recycle, and partial desorbent-port closing.

ABSTRACT

If a multi-component monosugar mixture including fucose was used as the substrates for the Klebsiella oxytoca fermentation, it could offer the following two benefits simultaneously; (i) the removal of all monosugars other than fucose, and (ii) the acquisition of 2,3-butanediol (BD). To utilize such two benefits in favor of the economical efficiency of the fucose production process, it is essential to accomplish a high-purity separation between fucose and BD on the basis of a highly-economical mode. To address this issue, we aimed to develop a simulated moving bed (SMB) process for continuous-mode separation of fucose and BD with high purities. It was first found that an Amberchrom-CG71C resin could become a suitable adsorbent for the separation of interest. The intrinsic parameters of fucose and BD on such proven adsorbent were determined, and then applied to the optimal design of the fucose-BD separation SMB. The capability of the designed SMB in ensuring high purities and high yields was experimentally verified. Finally, we devised two potential strategies to make a further improvement in product concentrations and/or desorbent usage while keeping the purities and yields of fucose and BD almost unchanged. The first strategy was based on partial extract-collection and partial extract-discard, which was found to result in 33% higher BD product concentration. The second strategy was based on partial extract-collection, partial extract-recycle, and partial desorbent-port closing, which could lead to 25% lower desorbent usage, 33% higher BD product concentration, and 7% higher fucose product concentration.