Tuning of Bacterial Cellulose Hydrogel Architecture during Fermentation through Polymer-Modified Growth Media

The formation of bacterial cellulose pellicles by Acetobacter xylinum is investigated in growth media supplemented with sodium alginate (SA) or carboxymethylcellulose (CMC). Both polymers influence bacterial cellulose assembly during growth, but through distinct physicochemical mechanisms. In SA-containing media, increased viscosity reduces bacterial mobility and promotes the formation of denser pellicles with reduced interlayer spacing and porosity, without substantially affecting cellulose production. In contrast, under the acidic culture conditions used in this study, CMC undergoes pH-dependent conformational changes and adsorption-mediated interactions with cellulose fibrils, promoting local aggregation and bundle formation while reducing pellicle thickness and dry mass. By tuning medium viscosity and fiber-polymer interactions during bacterial growth, it is possible to direct the assembly of cellulose nanofibrils, enabling the design of hydrogels with tailored density, porosity, and microstructural properties for applications such as biomedical scaffolds and tissue engineering matrices.