Semi-Hydrophobic Composite Cryogels Embedded with Bacterial Cellulose as Adsorbents for Separation of Phenyllactic...

Phenyllactic acid (PhLA) is one of important bio-based compounds with potential applications as a natural preservative, feed additive, pharmaceutical agent and polymer precursor in food, pharmaceutical, materials, and chemical industries. Microbial biosynthesis offers a sustainable and low-carbon route for the industrial production of PhLA. However, efficient purification remains a prominent challenge on account of the complex composition of fermentation broths. To address this issue, cryogelscharacterized by their interconnected supermacroporous structures and superior adsorption capabilities, have emerged as promising materials for the separation of bio-based products such as PhLA from complex feedstocks. In this work, a composite semi-hydrophobic poly(2-hydroxyethyl methacrylate-butyl methacrylate)-based cryogels embedded with bacterial nanocellulose was prepared via cryo-copolymerization under freezing conditions, followed by grafting with vinylbenzyl trimethylammonium chloride. The integration of hydrophobic and electrostatic functional groups enabled highly selective adsorption of PhLA. To further investigate the adsorption separation process, this study systematically evaluated the structural and adsorption characteristics of the cryogel. Molecular dynamics simulation was performed to elaborate on PhLA molecules at the microscopic level and clarify the binding mechanism with the functional ligands within the cryogel matrix. The regulatory effect of ionic strength on these interactions was also highlighted. Direct separation of PhLA from cell-containing fermentation broth was successfully achieved through chromatography using the cryogel, yielding a maximum purity of 96.4%, an overall average purity of 88.4%, and a total recovery of 87.2%, indicating that the semi-hydrophobic cryogel possesses excellent mechanical stability, high selectivity, and operational simplicity, underscoring its potential for applications in industrial separation and purification processes.