From Bacterial Cellulose Production by Komagataeibacter xylinus to Bacterial Cellulose Nanoparticles: A Standardized Enzymatic Approach

Abstract

Bacterial cellulose (BC) is a renewable biopolymer valued for its exceptional purity, biocompatibility, and mechanical strength, with broad applications in biomedicine and sustainable materials. However, achieving reproducible BC production and downstream processing remains a major challenge. Inoculum preparation is particularly difficult to standardize because cellulose-producing strains form pellicles that sequester cells, making optical density measurements unreliable. In addition, recovery and drying procedures can alter fiber accessibility, and enzymatic hydrolysis conditions are often inconsistently defined and lack proper enzyme activity assessment. These issues contribute to substantial variability in BC-derived nanoparticle yields. This protocol describes the production of BC from Komagataeibacter xylinus DSMZ 6513, including culture medium preparation, inoculum generation, and scaling up under static cultivation conditions. It further details BC pellicle purification using NaOH, followed by pulping, freeze-drying, and milling to ensure material stability during storage and use. BC hydrolysis is performed with commercially available cellulase from Trichoderma reesei, with enzyme activity quantified prior to each reaction to ensure reproducibility. This standardized approach enables the reproducible production of bacterial cellulose nanoparticles (BCNPs). The protocol also includes minimal morphological characterization methods. By standardizing culture, recovery, and hydrolysis steps, the workflow reduces experimental variability and improves comparability across laboratories. Overall, it provides an accessible and reproducible method for generating BC and BCNPs of consistent quality without the need for specialized instrumentation. Key features • Standardized inoculum preparation that does not rely on optical density measurements, ensuring reproducible starting conditions for cellulose-producing strains. • Controlled recovery and freeze-drying procedures that preserve fiber accessibility and promote consistent enzymatic hydrolysis outcomes. • Use of commercially available Trichoderma reesei cellulase (≥700 units/g), with enzyme dosage defined by measured activity according to a publicly available Megazyme protocol. • Minimal but robust morphological characterization methods to assess material quality.