Bacterial Cellulose Pellicles Research Articles

Multifactorial Optimization and Characterization of Bacterial Cellulose by Plackett-Burman and Taguchi Designs

Bacterial cellulose (BC) has distinctive structural, physical, functional, and chemical characteristics. Recently, there has been growing interest in mass-producing BC for industrial uses to achieve greater cost-effectiveness and productivity in cellulose synthesis. This study aimed to enhance the productivity of BC by utilizing the Plackett-Burman Design to determine the optimal media composition and Taguchi's design for optimizing the culture parameters by Gluconacetobacter xylinus NRRL B-469. The impact of eleven cultural components on BC production was assessed using the Plackett-Burman Design. The results indicated that the variables with the greatest influence on BC production were Mannitol at a concentration of 25 g/L, H2SO4–heat-treated molasses at 110 ml, CSL at 80 ml, Citric acid at 1.15 g/L, and Na2HPO4 at 2.7 g/L. These optimal medium compositions resulted in a higher BC yield of 9.5 g/l. Furthermore, Taguchi's design accurately forecasted a yield almost double that of BC (18.04 g/l) under ideal production circumstances. The composition of the solution is as follows: Mannitol 25 g/L, H2SO4–heat-treated molasses 110 mL, CSL is 120 mL, citric acid 0.5 g/L, Na2HPO4 5 g/L. The total volume of the solution is 100 mL. The incubation period is 246 hours. The pH level is 5 and the temperature is maintained at 30oC. Additionally, the dried BC membrane was characterised using Scanning Electron Microscopy to establish its morphological structure and purity, X-ray Diffraction to assess its crystallinity, and FT-IR to analyse its chemical structure and functional groups. BC has fibrils that are somewhat thinner and have a more condensed structure, ranging from 73.9 to 161.0 nm. The utilization of experimental techniques, such as the Taguchi method and Plackett–Burman design, can serve as a valuable means to enhance the synthesis of bacterial cellulose pellicle. That could be serve as a promising material for specific applications.

Bacterial Cellulose Purification with Non-Conventional, Biodegradable Surfactants

Bacterial cellulose (BC) is a versatile biopolymer with significant potential across biomedical, food, and industrial applications. To remove bacterial contaminants, such as protein and DNA, BC pellicles undergo purification, which traditionally relies on harsh alkali treatments, such as sodium hydroxide or strong surfactants, which present environmental concerns. In response, this study evaluates the efficacy of various non-conventional surfactants—both non-biodegradable and biodegradable—as alternatives for BC purification. Among the surfactants tested, sodium cocoyl isethionate (SCI), a mild anionic and biodegradable surfactant, emerged as particularly effective, achieving an 80.7% reduction in protein content and a 65.19% reduction in double-stranded DNA (dsDNA) content relative to untreated samples. However, these advantages were not without additional challenges, such as the appearance of residual surfactants. Given SCI’s promising performance and biodegradability, it was further examined in two-step treatment protocols; additionally, sodium dodecyl sulfate (SDS) was also examined as a more traditional anionic surfactant as well as NaOH. For the two-step treatment protocol, BC pellicles were treated with one reagent for 3 h, followed by a second reagent for an additional 3 h. Notably, by using NaOH as the final step in the two-step treatment protocol, residual surfactant was not detected in the FTIR analysis. Overall, this work demonstrates that SCI, in addition to subsequent NaOH treatment, can be used as a surfactant-based approach for BC purification, representing a potential environmentally friendly alternative to traditional surfactant-based approaches for BC purification.

Novel papain and bacterial cellulose/alginate biocomposites for bioactive wound dressing

The potential of bacterial cellulose membranes in the biomedical field as a wound dressing agent including contributing to chronic wound infections. The occurrence of antibiotic resistance mechanisms that protect bacteria, this is a problem that needs to be considered in the wound healing process. To accelerate the wound healing process and avoid infection, it is necessary to choose the right wound dressing material. In this study, alginate biopolymers and papain enzymes immobilized on BC pellicle to protect wounds from infection by several bacteria were investigated. The purpose of this study was to obtain a BC composite that has the potential as antibacterial wound dressing. Antibacterial activity, biodegradability, and hemocompatibility were assessed. The 8% papain concentration showed the strongest antibacterial effect against S. aureus (5.9 ± 5.05 mm) and E. coli (6.4 ± 6.27 mm). All composites exhibited high biodegradability (94–97% weight loss). The 6% and 8% papain concentrations were hemocompatible, with low hemolysis rates (<2%). These results suggest that BC/AG/Papain composites have the potential as effective antibacterial wound dressings.

Impact of Carbon Source on Bacterial Cellulose Network Architecture and Prolonged Lidocaine Release.

The biosynthesis of bacterial cellulose (BC) is significantly influenced by the type of carbon source available in the growth medium, which in turn dictates the material's final properties. This study systematically investigates the effects of five carbon sources-raffinose (C18H32O16), sucrose (C12H22O11), glucose (C6H12O6), arabinose (C5H10O5), and glycerol (C3H8O3)-on BC production by Komagataeibacter hansenii. The varying molecular weights and structural characteristics of these carbon sources provide a framework for examining their influence on BC yield, fiber morphology, and network properties. BC production was monitored through daily measurements of optical density and pH levels in the fermentation media from day 1 to day 14, providing valuable insights into bacterial growth kinetics and cellulose synthesis rates. Scanning electron microscopy (SEM) was used to elucidate fibril diameter and pore size distribution. Wide-angle X-ray scattering (WAXS) provided a detailed assessment of crystallinity. Selected BC pellicles were further processed via freeze-drying to produce a foam-like material that maximally preserves the natural three-dimensional structure of BC, facilitating the incorporation and release of lidocaine hydrochloride (5%), a widely used local anesthetic. The lidocaine-loaded BC foams exhibited a sustained and controlled release profile over 14 days in simulated body fluid, highlighting the importance of the role of carbon source selection in shaping the BC network architecture and its impact on drug release profile. These results highlight the versatility and sustainability of BC as a platform for wound healing and drug delivery applications. The tunable properties of BC networks provide opportunities for optimizing therapeutic delivery and improving wound care outcomes, positioning BC as an effective material for enhanced wound management strategies.

Bacterial cellulose with CHAPK-mediated specific antimicrobial activity against Staphylococcus aureus

Wound healing represents a complex biological process often hampered by bacterial infections, in particular those caused by Staphylococcus aureus, which is already multiresistant to many antibiotics. In this sense, enzybiotics have additional advantages over conventional antibiotics, since they provide pathogen specificity and do not contribute to antibiotic resistance. However, their soluble administration at the wound site would result in enzyme leakage. On the other hand, bacterial cellulose (BC) pellicles present a very promising dressing and scaffold, given its high purity, water retention capacity, and barrier effect in the wound against possible contaminants. In this study, we present a novel approach that incorporates the enzybiotic CHAPK into BC to develop functionalized membranes that exhibit targeted and controlled antimicrobial activity against S. aureus. The kinetic tests revealed a continuous loading of the enzybiotic into BC until it reaches a maximum and a two-stage release process, characterized by an initial fast release followed by a sustained release. Attenuated total Reflection Fourier Transform Infrared Spectroscopy (ATR-FTIR), Scanning Electron Microscopy (SEM), and Confocal Laser Scanning Microscopy (CLSM) confirmed the incorporation and the preferential surface localization of CHAPK within the BC membranes. Finally, the BC/CHAPK materials demonstrated the sustained reduction of up to 4 logarithmic units in the viability of S. aureus. Overall, the biomaterials developed here exhibit promising antimicrobial efficacy against S. aureus, offering a potential strategy for wound management and skin infection control while maintaining unharmed the commensal skin microbiota, which impairment could compromise the integrity of the skin barrier function.

Inducible biosynthesis of bacterial cellulose in recombinant Enterobacter sp. FY-07

Bacterial cellulose (BC) is an extracellular polysaccharide with myriad unique properties, such as high purity, water-holding capacity and biocompatibility, making it attractive in materials science. However, genetic engineering techniques for BC-producing microorganisms are rare. Herein, the electroporation-based gene transformation and the λ Red-mediated gene knockout method with a nearly 100 % recombination efficiency were established in the fast-growing and BC hyperproducer Enterobacter sp. FY-07. This genetic manipulation toolkit was validated by inactivating the protein subunit BcsA in the cellulose synthase complex. Subsequently, the inducible BC-producing strains from glycerol were constructed through inducible expression of the key gene fbp in the gluconeogenesis pathway, which recovered >80 % of the BC production. Finally, the BC properties analysis results indicated that the induced-synthesized BC pellicles were looser, more porous and reduced crystallinity, which could further broaden the application prospects of BC. To our best knowledge, this is the first attempt to construct the completely inducible BC-producing strains. Our work paves the way for increasing BC productivity by metabolic engineering and broadens the available fabrication methods for BC-based advanced functional materials.

Aerogel‐like biodegradable acoustic foams of bacterial cellulose

AbstractWe report the first work on the development of biodegradable acoustic foams from self‐grown bacterial cellulose (BC) from kombucha solution and green processing techniques. Kombucha BC‐agar and kombucha BC‐polyvinyl alcohol foams were fabricated by using slurries of BC pellicles mixed with the additives, froze for 24 h, and recast into foams using the freeze‐drying method. The foams were aerogel‐like with a density 20 kg/m3, thermally stable upto 220 °C, and crystallinity ~74%. Morphological analysis revealed macropores with coarse walls in agar‐based foams, whereas the PVA‐based foams comprised a polydisperse pore network with coarse walls. A broadband absorption was observed with a maximum of 0.4 for the 2.5‐mm‐thick single‐layer foams and 0.9 for the 12‐mm‐thick multilayer foams. The sound absorption was found to be on par with the biodegradable foams of agar and other cellulose‐rich materials such as agricultural residue, yet with a lightweight. Being largely porous, the foams had little transmission loss. As the densities and the crystallinities of these foams are tunable by the addition of other polymers, the results from this study provide scope to explore BC‐based lightweight materials for large‐scale fabrication suitable for sound absorption over specific regimes.

Simultaneous use of two-step fermentation and in-situ addition of chitosan oligosaccharide improving bacterial cellulose pellicle in the synthesis and various behaviors

Simultaneous use of two-step fermentation and in-situ addition of chitosan oligosaccharide improving bacterial cellulose pellicle in the synthesis and various behaviors

Karakterisasi Biofilm Selulosa Bakteri dengan Modifikasi Gliserol secara Ex Situ

Bacterial cellulose (BC) is biomaterial from bacterial fermentation that contain high purity of cellulose, but 90% of BC pellicles retained water from the fermentation process. In this study, BC was modified with glycerol immersion in different concentrations (0%; 2,5%; 5%; 7,5%; 10%). For wide application, water content on BC must be removed by drying. Various oven drying condition are temperature 80 °C and 120 °C and time 60 minutes. The physical and mechanical properties of the dried BC biofilm were determined including tensile strength and elasticity. BC biofilm bound was identified by FTIR and EDX. The results showed that glycerol concentration was able to increase biofilm elasticity from 3.46% to 27.743%. However, glycerol immersion above 7.5% caused a decrease in the tensile strength of BC biofilm. The drying variation of 120 °C produces the highest tensile strength of 7.161 MPa when soaked in 7.5% glycerol. The drying variation of 80 °C produced a biofilm with the best elasticity of 27.473%. The results of FTIR and EDX analysis confirmed that there were differences in the contents of the modified BC.

In‐Situ Fabrication Process of Bacterial Cellulose compositesfor Soft Robots

Bacterial cellulose (BC) produced by acetic acid bacteria is a promising biomaterial that exhibits exceptional mechanical strength, biocompatibility, and biodegradability. In this study, we have successfully fabricated BC composites with various materials such as alumina fibers, zirconia particles, carbon nanotubes, and magnetic particles by adding each material to the culture medium. We also demonstrate the actuation of BC‐magnetic particle composites by a magnetic field. Furthermore, we have achieved the patterning of arbitrarily shaped patterns onto BC pellicles by placing templates in the culture medium. These findings suggest that BC composites have the potential to be applied in various fields such as tissue engineering and drug delivery. © 2024 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC.

Bacterial cellulose produced by Medusomyces gisevii on glucose and sucrose: biosynthesis and structural properties

In this work, the effects of carbon sources and culture media on the production and structural properties of bacterial cellulose (BC) synthesized by Medusomyces gisevii have been studied. The culture medium was composed of different initial concentrations of glucose or sucrose dissolved in 0.4% extract of plain green tea. Parameters of the culture media (titratable acidity, substrate conversion degree etc.) were monitored daily for 20 days of cultivation. The BC pellicles produced on different carbon sources were characterized in terms of biomass yield, crystallinity and morphology by field emission scanning electron microscopy (FE-SEM), atomic force microscopy and X-ray diffraction. Our results showed that Medusomyces gisevii had higher BC yields in media with sugar concentrations close to 10 g L−1 after a 18–20 days incubation period. Glucose in general lead to a higher BC yield (173 g L−1) compared to sucrose (163.5 g L−1). The BC crystallinity degree and surface roughness were higher in the samples synthetized from sucrose. Obtained FE-SEM micrographs show that the BC pellicles synthesized in the sucrose media contained densely packed tangles of cellulose fibrils whereas the BC produced in the glucose media displayed rather linear geometry of the BC fibrils without noticeable aggregates.

The production and characterization of bacterial cellulose pellicles obtained from oil palm frond juice and their conversion to nanofibrillated cellulose

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.

Structural properties of optically clear bacterial cellulose produced by Komagataeibacter hansenii using arabitol.

Bacterial cellulose (BC) exhibits beneficial properties for use in biomedical applications but is limited by its lack of tunable transparency capabilities. To overcome this deficiency, a novel method to synthesize transparent BC materials using an alternative carbon source, namely arabitol, was developed. Characterization of the BC pellicles was performed for yield, transparency, surface morphology, and molecular assembly. Transparent BC was produced using mixtures of glucose and arabitol. Zero percent arabitol pellicles exhibited 25% light transmittance, which increased with increasing arabitol concentration through to 75% light transmittance. While transparency increased, overall BC yield was maintained indicating that the altered transparency may be induced on a micro-scale rather than a macro-scale. Significant differences in fiber diameter and the presence of aromatic signatures were observed. Overall, this research outlines methods for producing BC with tunable optical transparency, while also bringing new insight to insoluble components of exopolymers produced by Komagataeibacter hansenii.

In situ visualization of the tensile deformation mechanism of bacterial cellulose network

Bacterial cellulose (BC) pellicles are strong hydrogels composed of nanofibril networks. These hydrogels are considered attractive materials for synthetic biology, in which biological systems or modules are designed with user-defined functions. To develop BC-based materials with tailored mechanical properties, elucidation of the tensile deformation mechanism is essential. Therefore, in this study, BC hydrogels were fluorescently labeled, and the fiber network under tensile deformation was observed in situ using a device for simultaneous confocal laser scanning microscopy and uniaxial tensile deformation. As a result, strain-dependent deformation modes were identified and the generation of stress paths (stress-loaded fiber segments) during deformation was visualized. Furthermore, characteristic relaxation spectra of the nanofiber network were obtained from stress-relaxation measurements, revealing the existence of a first-order relaxation mode at approximately 1 s and higher-order relaxation modes over a long time period of 102–105 s. On this basis, we proposed a tensile deformation model of the BC hydrogel characterized by rearrangements of fiber segments accompanied by cleavage of cross-links. This model is expected to facilitate synthetic biology using BC hydrogels.

Improved degradability and mechanical properties of bacterial cellulose grafted with PEG derivatives

New functional materials based on bacterial cellulose (BC) grafted with poly(ethylene glycol) PEG derivatives for food packaging applications and a facile method for assessing the degradation rates of the final materials are presented. Two types of materials were obtained by grafting the BC films (BCF), respectively lyophilized BC pellicles (BCL) with three PEG derivatives of different molecular weights through radical polymerization. The BC based polymer materials were characterized by SEM, FT-IR, contact angle measurements, and TGA. Tensile tests and DMA analysis were used to compare the two types of materials in terms of shear-modulus, tensile strength and performance giving suitable information for food packaging applications. A new degradation evaluation method, that we propose herein, offers quantitative information about the degradation process in contrast with the SEM analysis, primarily used in literature, which is not decisive in all cases because it characterizes only small parts of the sample. The degradation rates evidenced that the PEG derivatives of higher molecular weight grafted on the surface of BCF led to an acceleration of the degradation process compared with the pristine samples. A good correlation was obtained between the samples analyzed by SEM after the degradation process and their degradation rates were mathematically determined.

Bio-inspired fabrication of adsorptive ultrafiltration membrane for water purification: Simultaneous removal of natural organic matters, lead ion and organic dyes

Conventional ultrafiltration membrane is difficult to achieve the multi-component removal of water contaminants including macromolecules and small ions. Meanwhile, a large number of petrochemical-based polymers as membrane material is raising concerns about environmental risk. In this study, we present a feasible way for the manufacture of multifunctional cellulose-based nanocomposite membranes via bio-fabrication by Acetobacter xylinus for water purification. The harvested bacterial cellulose (BC) pellicle was coated by polydopamine (PDA) as a functional layer and molecular linker to immobilize carboxylated cellulose nanocrystals (C-CNCs) to prepare BC/PDA14h/CNCs membrane (BCM/PDA14h/CNCs). The composited PDA and C-CNCs on the BC nanofibers endowed the membrane with a maximum adsorption capacity of up to 167.80 mg g−1 for Pb2+, and 251.58 mg g−1 for methylene blue (MB). Multiple contaminants (heavy metals, organic dyes, and natural organic matter (NOM)) can also be treated by BCM/PDA14h/CNCs simultaneously during the dynamic filtration process. The removal efficiency of BCM/PDA14h/CNCs against the mixture of metal ions is inversely proportional to the radius of hydrated ions. The selective separation studies on binary dye mixtures showed that the separation efficiency of the membrane is mainly related to the electronegativity of dyes. The BCM/PDA14h/CNCs exhibited preferential adsorption for cationic dyes, with a separation efficiency was up to 98%. Dynamic fouling experiments confirmed that the BCM/PDA14h/CNCs presented excellent antifouling performance and showed a high flux recovery ratio. The multifunctional characteristic, high removal efficiency, excellent reusability and stability as well as environmentally friendly feature of the prepared membrane in the present study provide a sustainable approach for membrane fabrication and promising application in water purification.

Enhancement of Inhibition of the Pseudomonas sp. Biofilm Formation on Bacterial Cellulose-Based Wound Dressing by the Combined Action of Alginate Lyase and Gentamicin

Bacterial biofilms generally contribute to chronic infections, including wound infections. Due to the antibiotic resistance mechanisms protecting bacteria living in the biofilm, they are a serious problem in the wound healing process. To accelerate the wound healing process and avoid bacterial infection, it is necessary to select the appropriate dressing material. In this study, the promising therapeutic properties of alginate lyase (AlgL) immobilised on BC membranes for protecting wounds from Pseudomonas aeruginosa infection were investigated. The AlgL was immobilised on never dried BC pellicles via physical adsorption. The maximum adsorption capacity of AlgL was 6.0 mg/g of dry BC, and the equilibrium was reached after 2 h. The adsorption kinetics was studied, and it has been proven that the adsorption was consistent with Langmuir isotherm. In addition, the impact of enzyme immobilisation on bacterial biofilm stability and the effect of simultaneous immobilisation of AlgL and gentamicin on the viability of bacterial cells was investigated. The obtained results showed that the AlgL immobilisation significantly reduced the amount of polysaccharides component of the P. aeruginosa biofilm. Moreover, the biofilm disruption by AlgL immobilised on BC membranes exhibited synergism with the gentamicin, resulting in 86.5% more dead P. aeruginosa PAO-1 cells.

Increasing Electrical Conductivity of Bacterial Cellulose/Polypyrrole Bio Composite Films Prepared Using the Pulling Technique

This research has found a new approach to improving the conductivity of bacterial cellulose BC/Ppy bio composite films prepared using pulling. A wet BC pellicle is immersed in a liquid Ppy semiconductor for 30 minutes. The wet films was pulled out using a tensile testing machine. The results show that, after pulling, the conductivity of the films became better parallel to the sample drawing direction. Compared to the non-pulled out film, the pulled out film had higher conductivity (σ = 19.2 x 10-3 S/cm), increasing by 153%. The conductivity of films can still improve significantly because deformation during sample preparation in wet conditions.

Functional bacterial cellulose nanofibrils with silver nanoparticles and its antibacterial application

Bacterial cellulose (BC) with good biocompatibility and superior mechanical properties has broad applications. BC functionalized with silver nanoparticles (AgNPs) has been assessed as an antimicrobial membrane for wound-healing treatment. During the AgNPs synthesis, avoiding the use of toxic chemicals is very necessary for the development of environmentally friendly procedures. Herein, a Komagataeibacter xylinus-based direct biosynthetic method to fabricate D-Saccharic acid potassium salt (SA)-grafted BC (SABC) through in situ bacterial metabolism was firstly explored. Subsequently, the SABC pellicles were immersed in AgNO3 solution for ion-exchanged process, and the silver nanoparticles (AgNPs) with diameter of ∼25.2 nm were in situ synthesized on SABC nanofiber surfaces by thermal reduction instead of using a reducing agent. The morphology and microstructure of SABC/AgNPs pellicles were analyzed by field-emission scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectra. Moreover, antibacterial activity measurement performed against the Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) by disk diffusion and plate count methods, showed high-efficiency bacteria-killing performance of SABC/AgNPs pellicles. This work proposed a new method by using microbial metabolism to prepare BC pellicles with functional groups, and antimicrobial films containing AgNPs was prepared by thermal reduction, exhibiting valuable prospects in wound healing treatment.

A novel static cultivation of bacterial cellulose production from sugar beet molasses: Series static culture (SSC) system

In bacterial cellulose (BC) production, we developed a new static cultivation system named series static culture (SSC) to eliminate air limitation problem encountered in conventional static culture (CSC). In SSC system, the fermentation broth at the bottom of BC pellicle produced in initial culture medium is transferred to the next empty sterile culture medium at the end of a certain fermentation period. This procedure was performed until BC production ceased. Fermentation experiments were carried out using Gluconacetobacter xylinus NRRL B-759 and sugar beet molasses at 30 °C and initial pH 5. Also, some quality parameters of produced BC pellicles were determined. Final pH at the stages of SSC system was higher that of the initial pH due to sugar content (sucrose) of molasses and microorganism used. Total BC production increased with increasing sugar concentration in SSC. As a result, an increase of 22.02 % in BC production was achieved using developed SSC. FT-IR spectra of all BC pellicles produced were typical spectra. The absorption bands at the relevant wavenumbers identify the mode of vibrations of the created chemical bonds arising at the BC surface such as OH, CH, H-O-H, C-O-C, and C-OH. XRD analyses showed that the crystallinity index values of BC obtained from CCS and SSC were high. The form of produced all BC pellicles is generally Cellulose I. Removal of surface moisture and depolymerisation of carbon skeleton were determined from TGA-DTA thermograms. SEM images showed that the BC samples produced had nano-sized cellulose fibrils which were aggregated in fermentation media containing molasses. Finally, the BC samples, especially in molasses media, having high mechanical strength and WHC were found.