Development of an efficient process for recovery of fucose in a multi-component mixture of monosugars stemming from defatted microalgal biomass

Research progress on the functions, preparation and detection methods of l-fucose

l-fucose is a six-carbon sugar that has potential applications in many fields. It exerts antitumor effects and could relieve intestinal disease. It exhibits potential as an emulsifier in the food industry. It is also used as a functional food and in anti-aging skincare products. However, at present, it is not possible to prepare high-purity l-fucose on a large scale, and its preparation needs further development. This review summarizes the preparation methods of l-fucose including chemical synthesis, enzymatic synthesis, microbial fermentation, and separation and purification from algae. The detection methods of l-fucose are also introduced in detail, such as l-fucose-specific lectin, detection l-fucose dehydrogenase, cysteine-sulfuric acid method, high-performance liquid chromatography, gas chromatography, and biosensors. In this review, the properties and pharmacological effects of l-fucose; preparation methods, and the commonly used detection methods of l-fucose are reviewed to serve as a reference material.

Structural characterization of fucose-containing disaccharides prepared from exopolysaccharides of Enterobacter sakazakii

Fucose-containing oligosaccharides (FCOs) have important applications in the food, medicine, and cosmetics industries owing to their unique biological activities. The degradation of microbial fucose-containing exopolysaccharide (FcEPS) is a promising strategy for obtaining FCOs, and bacteriophage-borne glycanase is a useful tool for degrading FcEPS. Here, we aimed to obtain FCOs using bacteriophage-borne glycanase to depolymerize FcEPS from Enterobacter sakazakii. The FcEPS was mainly composed of l-fucose (42.72 %), d-galactose (20.59 %), and d-glucose (21.81 %). Based on the results of nuclear magnetic resonance and mass spectrometry, the obtained FCOs were disaccharide fragments with backbones of β-d-Glcp-(1→4)-β-l-Fucp and α-d-Galp-(1→3)-β-l-Fucp, respectively. So far, few studies of disaccharides prepared from FcEPS have been reported. This study demonstrated that the FcEPS of E. sakazakii was a reliable fucose-containing disaccharide source and that bacteriophage-borne glycanase was an effective degradation tool for obtaining FCOs fragments from FcEPS.

Optimal design of a simulated-moving-bed chromatographic process for high-purity separation of acetoin from 2,3-butanediol in a continuous mode

For the high-purity production of acetoin or 2,3-butanediol (BD) from related fermentation processes, it is essential to accomplish a detailed separation between acetoin and BD in an economical mode. To address this issue, we aimed to develop a highly-efficient simulated-moving-bed (SMB) process for the continuous-mode separation of acetoin from BD with high purity and small loss. As a first step for this task, the adsorption and mass-transfer parameters of acetoin and BD on a proven adsorbent were estimated while assuming that BD isomers (meso-BD and DL-BD) would be identical in adsorption and mass-transfer behaviors. The resultant parameters from such estimation were applied to the optimal design of the acetoin-BD separation SMB. The designed SMB was then experimentally investigated, which revealed that some sign of BD isomerism occurred in the SMB column-profile data and thus had an adverse effect on the SMB separation performance. To resolve this problem, the individual parameters of BD isomers were determined on the basis of the SMB column-profile data and an inverse-method principle. The resulting parameters of BD isomers were used in the re-design of the target SMB, which was then experimentally checked for its separation performance. It was confirmed that such SMB re-designed in consideration of BD isomerism was quite effective in the continuous-mode separation of acetoin from BD with high purity (> 99.2%) and small loss (< 1.52%).

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

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.

Optimization of production rate, productivity, and product concentration for a simulated moving bed process aimed atfucose separation using standing-wave-design and genetic algorithm

The effectiveness of a simulated moving bed (SMB) technology in the continuous separation of fucose from a multi-component monosugar mixture, which stemmed from defatted microalgae, has recently been identified. To guarantee high economical efficiency of such fucose-production method, the comprehensive optimization of the relevant fucose-separation SMB process needs to be accomplished such that its production rate (Prate) and/or productivity (Prod) can be maximized while meeting the requirements on fucose product concentration (C_prod,F) and pressure drop (ΔP_SMB). To resolve this issue, the SMB optimization program based on standing-wave-design method and genetic algorithm was prepared and then applied to the fucose-separation SMB optimization. It was found that the Prate, under a given particle size, could reach its maximum when the column length was selected to create a balance between the effects of the two limiting factors related to C_prod,F and ΔP_SMB. It was also found that the Prate was governed by fucose yield, if the SMB would be in need of a relatively high C_prod,F; otherwise, the Prate was governed by feed flow rate. If the particle size of the SMB adsorbent was fixed at one of the commercially available ones, the SMB conditions leading to the highest Prate and the highest Prod coincided with each other. By contrast, if the particle size was included as one of optimization variables, the Prate and Prod represented a trade-off relationship. Finally, it was confirmed from the simultaneous optimization for Prate and Prod that the increase of particle size improved Prate at the cost of Prod, thereby causing the maximum Prod to be always attained at a smaller particle size than the maximum Prate regardless of the target C_prod,F level.