Biosynthetic fingerprints and strain-specific characterization of bacterial cellulose from...

Bacterial cellulose (BC) is a nanostructured biopolymer renowned for its high crystallinity, exceptional water-holding capacity, and biocompatibility. While interspecies differences in BC properties are documented, comprehensive insights into strain-level biosynthetic variability within and across Komagataeibacter species remain limited. In this study, ten BC-producing strains were isolated from vinegar samples of diverse botanical origins and identified via 16S rRNA sequencing as belonging to three species: K. europaeus, K. medellinensis, and K. xylinus. Despite the limited taxonomic diversity, the isolates exhibited ten distinct "biosynthetic fingerprints," as evidenced by pronounced variations in production yield, micro- and nanostructural morphology (FE-SEM), chemical functionality (FTIR), crystallinity (XRD), thermal stability (TGA), and water-holding capacity (WHC). Quantitatively, BC yields ranged from 2.10 to 3.01 g L⁻¹ , crystallinity indices from 34.5 % to 65.6 %, DTG_max from 337.4 °C to 372.1 °C, and WHC from 87.3 % to 95.7 %. Interestingly, some low-crystallinity samples demonstrated higher thermal stability, indicating that microstructural organization and fibril network compactness contribute significantly to thermal resistance beyond crystallinity alone. These findings establish that vinegar-derived Komagataeibacter strains harbor substantial strain-specific structural and functional heterogeneity, underscoring the necessity of strain-level selection and characterization when tailoring BC for advanced biomedical and industrial applications.