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This study explored the potential of using oil palm frond (OPF) juice as a fermentation medium for bacterial cellulose (BC) synthesis by Acetobacter xylinum 0416, followed by its conversion into nanofibrillated cellulose (BNFC). The effect of adding nitrogen sources to OPF juice on the BC yield and thickness was investigated, with corn steep liquor (CSL) showing the most promising results, increasing BC yield and thickness by six- and four-fold, respectively. The resulting BC-OPF+CSL pellicles demonstrated excellent thermal stability, high crystallinity and a large swelling ratio. The study also investigated the conversion of BC-OPF+CSL pellicles into BNFC using either homogenization, ultrasonication, or a combination of both. The combination of ultrasonication and homogenization produced the best results, disintegrating the BC fibers into BNFC with a diameter of 13–21 nm and water retention value of 6105%. Low BNFC crystallinity and thermal stability were also observed, indicating successful BC fibrillation. These findings suggest that OPF juice is a promising alternative fermentation medium for BC production and that combining ultrasonication and homogenization is a simple and safe method for converting BC-OPF+CSL pellicles into BNFC. This research offers a potential eco-friendly solution for BC production and its conversion into value-added products such as BNFC.

This paper describes the interaction and properties of bacterial cellulose (BC)–ciprofloxacin composites synthesized by in situ incorporation method. Ciprofloxacin's susceptibility to BC's producer, Acetobacter xylinum 0416, was first tested to determine its inhibitory activity against the bacteria. In situ incorporation method was performed by introducing 0.2% (w/v) ciprofloxacin into Hestrin–Schramm medium at the onset of exponential phase of A. xylinum 0416 growth. Following a 10-day incubation at 28 °C, BC–ciprofloxacin composites were harvested and further characterised, while another BC–ciprofloxacin composite was harvested and purified prior to characterisation. The interaction between ciprofloxacin and BC was proven by the presence of quinolines and fluorine groups of ciprofloxacin on unpurified BC–ciprofloxacin composite and the reduction of crystallinity index as compared to the native BC. Moreover, deposited ciprofloxacin crystals on BC film and its composition were exhibited via SEM-Energy-dispersive X-ray analysis. Unpurified BC–ciprofloxacin film was determined to have strongly inhibited the following selected diabetic foot ulcer bacteria: E. coli, K. pneumoniae and P. aeruginosa. BC has the potential to be used as a wound dressing and a carrier for ciprofloxacin.

Bacterial cellulose (BC) is a biocompatible hydrogel with a three-dimensional (3-D) structure formed by a dense network of cellulose nanofibers. A limitation of using BC for applications in tissue engineering is that the pore size of the material (∼0.02-10μm) is smaller than the dimensions of mammalian cells and prevents cells from penetrating into the material and growing into 3-D structures that mimic tissues. This paper describes a new route to porous bacterial cellulose (pBC) scaffolds by cultivating Acetobacter xylinum in the presence of agarose microparticles deposited on the surface of a growing BC pellicle. Monodisperse agarose microparticles with a diameter of 300-500μm were created using a microfluidic technique, layered on growing BC pellicles and incorporated into the polymer as A. xylinum cells moved upward through the growing pellicle. Removing the agarose microparticles by autoclaving produced BC gels containing a continuous, interconnected network of pores with diameters ranging from 300 to 500μm. Human P1 chondrocytes seeded on the scaffolds, replicated, invaded the 3-D porous network and distributed evenly throughout the substrate. Chondrocytes grown on pBC substrates displayed a higher viability compared to growth on the surface of unmodified BC substrates. The approach described in this paper introduces a new method for creating pBC substrates with user-defined control over the physical dimensions of the pore network, and demonstrates the application of these materials for tissue engineering., (Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)