Bacterial Cellulose Pellicles Research Articles

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.

Structural and mechanical anisotropy in rheotactically aligned bacterial cellulose

In this work, we demonstrate the preparation of oriented bacterial cellulose from Komagataeibacter sucrofermentans by rheotactic growth in a simple and adaptable setup. The resulting materials were assessed by their yields, geometric densities, and by X-ray diffraction, scanning electron and optical microscopy, and mechanical testing. They exhibited large differences in toughness, resulting from differences in fracture strain or highly anisotropic strengths. Their growth characteristics, structural and mechanical anisotropies and crystalline phase characteristics are discussed and compared to statically grown references and to instances from the literature. Here, we consider the length scales of structural anisotropy in native bacterial cellulose pellicles, and the origin of mechanical anisotropy. Further, we identify a tentative limit on achievable structural alignment in bacterial cellulose, as well as a correlation between crystallinity and disorder in the crystalline phase of bacterial cellulose.

Effect of Homogenization Pressure on Bacterial Cellulose Membrane Characteristic Made from Pineapple Peel Waste

Many studies were conducted to maintain the environment by reducing the waste, especially pineapple peel waste. This study aims to explore the effect of various pressure of the homogenization process on bacterial cellulose membrane surface morphology and structure produced using extract of pineapple peel waste. The methods include the preparation of pellicle samples from the product of the fermentation process of Acetobacter xylinum using a medium from the extract of pineapple peel waste. Bacterial cellulose pellicles were crushed using a blender. Mashed bacterial cellulose pellicle then homogenized in High-Pressure Homogenizer with pressure variation of 0 bar, 150 bar, 300 bar, 450 bar, dan 600 bar then cast into a mold. The bacterial cellulose solutions were dried in an oven at 60°C for 8 hours. The dried bacterial cellulose membrane was analyzed using XRD for the structure and SEM analysis for the morphology. The results indicate that the crystalline properties of BCM were shifted after being treated by various pressure processing in a High-Pressure Homogenizer. It was found that the High-Pressure Homogenizer with higher pressure reduced the peak intensity, decreased crystalline index from 87% to 70%, and decreased the degree of crystalline from 88% to 77% without changing the cellulose structure. The higher pressure of the homogenization process causes the porosity of the membrane to be decreased.

Optimization and physicochemical characterization of bacterial cellulose by Komagataeibacter nataicola and Komagataeibacter maltaceti strains isolated from grape, thorn apple and apple vinegars.

Bacterial cellulose (BC) is a valuable biopolymer that is increasingly used in medical, pharmaceutical and food industries with its excellent physicochemical properties as high water-holding capacity, nanofibrillar structure, large surface area, porosity, mechanical strength and biocompatibility. Accordingly, the isolation, identification and characterization of potent BC producers from grape, thorn apple and apple vinegars were performed in this study. The strains isolated from grape and apple vinegars were identified as Komagataeibacter maltaceti and the strain isolated from thorn apple vinegar was identified as Komagataeibacter nataicola with 16S rRNA analysis. Optimized conditions were found as 8% dextrin, 1.5% (peptone + yeast extract) and 10% inoculation amount at pH 6.0 with a productivity rate of 1.15g/d/L, a yield of 8.06% and a dry weight of 6.45g/L for K. maltaceti, and 10% maltose, 1% (peptone + yeast extract) and 10% inoculation amount at pH 6.0 with a productivity rate of 0.96g/L/d, a yield of 5.35% and a dry weight of 5.35g/L for K. nataicola. Obtained BC from K. maltaceti and K. nataicola strains was more than 2.56- and 1.86-fold when compared with BC obtained from HS media and exhibited 95.1% and 92.5% WHC, respectively. Based on the characterization results, BC pellicles show characteristic FT-IR bands and have ultrafine 3D structures with high thermal stability. By means of having ability to assimilate monosaccharides, disaccharides and polysaccharide used in this study, it is predicted that both isolated Komagataeibacter species can be used in the production of biopolymers from wastes containing complex carbon sources in the future.

Gamma-Irradiated Bacterial Cellulose as a Three-Dimensional Scaffold for Osteogenic Differentiation of Rat Bone Marrow Stromal Cells

The effect of gamma-irradiation on bacterial cellulose (BC) was investigated in terms of improving its properties as scaffolds for tissue engineering. BC pellicles were exposed to 25, 50, and 75 kGy gamma-ray irradiation, and X-ray diffraction analyses showed that the crystallinity of the BC decreased as stronger irradiation accelerated BC’s degradation. Fourier transform infrared spectroscopy of the irradiated BC revealed the appearance of a new peak at 1724 cm–1, indicating the formation of a new carbonyl group due to the cleavage of glycosidic linkages of the BC. Rat bone marrow stromal cells seeded on the gamma-irradiated BC incubated in an osteogenic medium for 14 days produced calcium, a late marker for osteogenic differentiation, as shown by Alizarin Red S (ARS) staining. Gamma-irradiated BC with higher irradiation doses showed intense ARS staining indicating higher calcium deposition. These findings demonstrate the feasibility of using gamma-irradiated BC as a cytocompatible 3D scaffold for bone tissue regeneration.

Liquid-crystalline ordering in bacterial cellulose produced by Gluconacetobaсter hansenii on glucose-containing media

This research is dedicated to the studies of the microscale morphology of bacterial cellulose (BC) obtained by means of static cultivation of Gluconacetobacter hansenii GH-1/2008. We found that the microscale morphology depended on the BC production rate that was varied by using different glucose concentrations in the cultivation medium. It was revealed that at higher production rates, BC fibrils were aligned in a liquid-crystalline-like (LC-like) order. The observed helical alignment was always left-handed. The half-periods of the helix varied from 50 μm to 150 μm depending on the cultivation conditions. The mechanical and water absorption properties of the obtained BC pellicles were measured. The former correlated mainly with the density of the samples; the latter were the best for films with layered structure, where the BC had segregated into fleece sheets separated by gaps with low density of fibrils.

Reproducibility of Bacterial Cellulose Nanofibers Over Sub-Cultured Generations for the Development of Novel Textiles.

The textile industry is in crisis and under pressure to minimize the environmental impact on its practices. Bacterial cellulose (BC), a naturally occurring form of cellulose, displays properties superior to those of its cotton plant counterpart, such as enhanced purity, crystallinity, tensile strength, and water retention and is thus suitable for an array of textile applications. It is synthesized from a variety of microorganisms but is produced in most abundance by Komagataeibacter xylinus. K. xylinus is available as a type strain culture and exists in the microbial consortium commonly known as Kombucha. Whilst existing literature studies have described the effectiveness of both K. xylinus isolates and Kombucha in the production of BC, this study investigated the change in microbial communities across several generations of sub-culturing and the impact of these communities on BC yield. Using Kombucha and the single isolate strain K. xylinus as inocula in Hestrin and Schramm liquid growth media, BC pellicles were propagated. The resulting pellicles and residual liquid media were used to further inoculate fresh liquid media, and this process was repeated over three generations. For each generation, the thickness of the pellicles and their appearance under SEM were recorded. 16S rRNA sequencing was conducted on both pellicles and liquid media samples to assess changes in communities. The results indicated that the genus Komagataeibacter was the most abundant species in all samples. Cultures seeded with Kombucha yielded thicker cellulose pellicles than those seeded with K. xylinus, but all the pellicles had similar nanofibrillar structures, with a mix of liquid and pellicle inocula producing the best yield of BC after three generations of sub-culturing. Therefore, Kombucha starter cultures produce BC pellicles which are more reproducible across generations than those created from pure isolates of K. xylinus and could provide a reproducible sustainable model for generating textile materials.

Bacterial cellulose: recent progress in production and industrial applications.

Bacterial cellulose (BC) is synthesized as a valuable extracellular biopolymer by several bacteria belonging to the genera of Acetobacter, Achromobacter, Komagataeibacter, Agrobacterium, Bacillus, Azotobacter, Sarcinia, Lactobacillus and Gluconacetobacter. Unlike plant cellulose, since BC does not contain lignin, hemicellulose, pectin, arabinose and other plant-derived contaminants, it can be obtained purely from the culture media without any purification processes. BC exhibits excellent physicochemical and mechanical properties such as purity, high crystallinity, transparency, porosity, high water holding capacity, ultrafine nanoscale fiber network, tensile strength, high degree of polymerization, high surface area, chemical stability and proton conductivity. In addition, BC has become an essential nanomaterial in many industrial processes as it is biocompatible, biodegradable and renewable. In this respect, researchers are focused on the production of BC using low-cost substrates, investigation of potential BC producers, optimization of cultivation conditions, and modification of BC pellicles with different procedures. Based on these researches, this review of recent progress in bacterial cellulose production, both in vivo and in vitro modifications of surface properties of BC and its industrial applications in different areas are discussed in this review.