Study on the dissolution and recovery mechanism of bacterial cellulose by green ionic liquid designed based on COSMO-RS

Bacterial cellulose (BC) is a natural polysaccharide polymer synthesized by microorganisms via fermentation. However, its complex three-dimensional network structure results in poor solubility, and traditional solvents, being toxic and energy intensive, limit its industrial application. In this study, 792 ionic liquids (ILs) were screened by Conductor-like screening model for realistic solvents (COSMO-RS) to predict BC solubility. Experimental validation revealed that 1,5-diazabicyclo[4.3.0]non-5-ene carboxylates ([DBN][AC]) achieved efficient dissolution of BC (DP = 9217) at a concentration of 6%. Combined with theoretical calculation and analysis, the molecular mechanism by which ILs disrupt the hydrogen bond network of BC was revealed. Regeneration experiments confirmed that the recovery rate of [DBN][AC] was as high as 93.8%. This study not only verified the reliability of the COSMO-RS model in guiding green solvent design, but also provides potential for the modified BC in future applications in the fields of active food packaging and as bioactive carriers.