( S )-3-Cyano-5-methylhexanoic acid (( S )-CMHA) is the key chiral intermediate of pregabalin . In this paper, an aqueous two-phase system (ATPS) was developed to extract ( S )-CMHA from nitrilase-catalyzed bioconversion broth. Inorganic salts and hydrophilic solvents were screened to form ATPS, among which an acetone/ammonium sulfate ATPS was investigated in detail, including phase diagram, effect of phase composition and stability of ( S )-CMHA. The maximum product recovery of 99.15% was obtained by an optimized ATPS system composed of 15% (w/w) ammonium sulfate and 35% (w/w) acetone with the removal of 99% cells and 86.27% proteins. The total ( S )-CMHA yield reached 92.11% after back-extraction. The recycling use of ammonium sulfate was investigated, and 93.10% of salt in the salt-rich phase was recovered with the addition of methanol. The results demonstrated the efficiency of the two-step extraction process for separation of ( S )-CMHA.
Aqueous two-phase system (ATPS) Pickering emulsions offer an attractive alternative to traditional oil–water emulsions (e.g., W/O, O/W, and O/W/O) for cosmetics, food processing, biotechnology, and particularly drug delivery. However, their scope of application is hindered by instability and toxicity concerns. Thus, developing a safe, oil-free, and long-term stable water-in-water (W/W) Pickering emulsion based on ATPS remains a critical challenge. Herein, we innovatively developed a safe, oil-free, long-term stable water-in-water (W/W) Pickering emulsion stabilized by green bamboo-derived hydrophobic lignin-containing cellulose nanofibers (H-LCNFs) for drug delivery applications. Hydrophobic H-LCNFs were prepared from bamboo via deep eutectic solvent (DES) pretreatment coupled with facile hydrophobization and employed to stabilize dextran (Dex)/polyethylene glycol (PEG) ATPS-based W/W emulsions. Systematic investigation of PEG/Dex composition, H-LCNF concentration (0.1–0.5 wt %), and pH revealed that 0.3 wt % H-LCNF conferred exceptional long-term stability (negligible droplet size change over 7 days) through electrostatic repulsion under pH 7–9, while elevated pH enhanced electrostatic repulsion, imparting significant pH responsiveness. Crucially, this system achieved resveratrol (RSV) encapsulation efficiency (62.11% to 95.6%) and retention rate (59.84% to 89.18%) surpassing the current level for hydrophobic drug delivery. Overall, this green, nontoxic ATPS stabilization strategy unlocks high-value lignocellulosic biomass utilization and provides a reference value for the research field of drug delivery.
A simple process is developed for the one-step preparation of dual-compartment alginate microcapsules with controlled size and structure from microfluid-generated water-in-water-in-oil (W/W/O) emulsion droplet. Unlike other methods that rely on transient W/W/O emulsion droplet, we introduce an aqueous two-phase system (ATPS) to form a stable W/W/O emulsion droplet as a template for preparing dual-compartment alginate microcapsules. Two different bioactive molecules are able to be spatially confined encapsulated in the shell and core of alginate microcapsules due to the partitioning effect of ATPS and the high viscosity of alginate solution. Moreover, an enzyme cascade reaction with a spatial confined glucose oxidase and horseradish peroxidase in the shell and core of alginate microcapsules confirms its excellent biocompatibility and high activity. This method provides a green platform for enzyme-catalyzed tandem reactions and controlled sequential release of multiple drugs based on alginate microcapsules.
危险品化学品经营许可证（带存储）