Construction and characterization of antimicrobial bacterial cellulose films containing Propionibacterium cells for fruit preservation application

Bacterial cellulose (BC) antimicrobial materials exhibit significant potential for applications across biomedical engineering and food packaging sectors owing to their distinctive nanofiber architecture and superior biocompatibility. Nevertheless, current fabrication approaches for antimicrobial BC materials, primarily based on physical/chemical modifications, suffer from intricate processing requirements and potential environmental hazards. In this study, an antimicrobial BC film was developed through a novel two-step co-cultivation strategy between aerobic BC-producing strain Komagataeibacter xylinus P1 and anaerobic antimicrobial metabolites-producing strain Propionibacterium freudenreichii ATCC 9616. The developed antimicrobial BC films showed high inhibition against Aspergillus niger and Penicillium citrinum, with inhibition zones of 26.8 ± 1.9 mm and 20.0 ± 1.2 mm, respectively. and showed strong antibactericidal effects against the foodborne pathogens Pseudomonas aeruginosa and Escherichia coli (inhibition rate 99.99% and 99.58%, respective). Crucially, the antimicrobial BC film showed improved thermal stability, and superior toughness and deformation capacity compared to pure BC films. Furthermore, the antimicrobial BC films demonstrated significantly delayed spoilage (33.3% incidence after 5 days storage) for strawberry preservation, outperforming both untreated and pure BC-wrapped controls. The two-step co-cultivation strategy developed herein provided a novel platform for fabricating advanced packaging materials, where BC nanomaterials serve as a matrix for in-situ embedding of antimicrobial metabolites produced from anaerobic bacteria.