Bacterial Cellulose Research Articles

Bacterial cellulose is a desirable biological macromolecule that can prevent obesity via modulating lipid metabolism and gut microbiota

Obesity has attracted great concern because of its undesirable effects on our life quality. Bacterial cellulose (BC) is a biological macromolecule that can improve gut homeostasis and lipid metabolism. However, its potential role in preventing obesity and associated mechanisms is still poorly understood. Herein, a supplement of BC was used to fully evaluate how it prevents obesity based on physio-biochemical and gut microbial analyses. Results showed that BC consumption helped decrease body and liver weight, and fat accumulation in kidney and epididymis. Correspondingly, glucose concentrations, total triglycerides, total cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol were reversed to the control levels. Consuming BC also improved liver fat metabolism and intestinal function, and alleviated ileum and epididymis inflammation. High-throughput sequencing suggested that a high-fat diet significantly decreased gut microbiota diversity, which could be reversed by consuming BC. A decreased Firmicutes and Proteobacteria and an increased Bacteroidetes following BC consumption were observed. The OTU-based analysis identified that Lachnospiraceae, Desulfovibrio, Lachnoclostridium, Blautia, Anaerotruncus, Bacteroides, Faecalibaculum, Bacteroidales S24–7 group, Prevotellaceae UCG-001 group, and Alloprevotella might be involved in obesity development or prevention. Our data suggest that BC is a good insoluble dietary fiber to prevent obesity via regulating lipid metabolism and gut microbiota.

Strong and ductile cellulose film improved by the in situ incorporation of a genetically engineered protein conjugated synthetic polymer during bacterial cellulose growth

Bacterial cellulose (BC) has been extensively applied to fabricate advanced biomaterials, although it remains challenging due to its poor toughness and water stability. Herein a genetically engineered protein-conjugated synthetic polymer is designed to improve BC film's strength and flexibility. Initially, the hybrid polymer is constructed by grafting Family 3 carbohydrate-binding modules (CBM3) to amphoteric polyacrylamide polymer (AmPAM), one of the paper industry's most widely used dry-strength agents. Then, the conjugated polymer is added to the culture medium of BC growth, enabling it to incorporate into the matrix of cellulose chains. The results show that the BC film modified by CBM3-AmPAM exhibits superior mechanical properties, registering 9.94 % in strain and 13.8 MJ/m3 in toughness, 12.1 and 8.0 folds over the sample with AmPAM addition only. Additionally, the BC film improved by CBM3-AmPAM has excellent gas resistance, thermal stability, and environmental endurance. The adsorption of CBM3-AmPAM on BC film revealed by quartz crystal microbalance with dissipation monitoring indicates that the adsorbed layer is thin and rigid, suggesting the strong interaction between the conjugated polymer and BC substrate. As a result of this reinforcing strategy, BC composites can be used in a wider range of applications.

Facile synthesis and antibacterial performance of novel biofilms based on bacterial cellulose from jackfruit rags, incorporating polyvinyl alcohol, Ag nanoparticles, and Eclipta prostrata extract

The advancements of antibacterial biofilms have received much attention in biomedical, wound healing, and food packaging. Here, we developed a novel bacterial cellulose (BC) through Acetobacter xylinum strains using jackfruit rags as a carbon source, under different fermentation conditions. The highest BC production of 5.668 g L–1 of dried weight BC was obtained from the medium with 1: 2 (w v–1) of jackfruit rags/water ratio, 4.5 initial pH and 9 days of incubation. Further bacterial cellulose was incorporated into mixture of polyvinyl alcohol (PVA), biogenic silver nanoparticles (AgNPs) and Eclipta prostrata extract (EPE) to develop antimicrobial films. The micromorphology, mechanical, and functionality of BC/PVA/AgNPs/EPE biofilms were compared with those of BC/PVA, BC/PVA/EPE, BC/PVA/AgNPs film precursors. The results showed that mechanical strength of BC/PVA/AgNPs/EPE biofilms increased, while their water vapor permeability significantly decreased. Fourier transform infrared and scanning electron microscopy revealed excellent compatibility between AgNPs, EPE and the BC/PVA matrix. The BC/PVA/AgNPs/EPE biofilm had strong antibacterial performance against Escherichia coli and Staphylococcus aureus, as the average zone of inhibitions were 18.5 ± 0.33 mm and 21.0 ± 0.3 mm, respectively. These outcomes suggest that the BC/PVA/AgNPs/EPE biofilm can be a good candidate for antibacterial food packaging.

Incorporation of polyvinyl alcohol in bacterial cellulose/polypyrrole flexible conductive films to enhance the mechanical and conductive performance

The integration of polypyrrole (PPy) into bacterial cellulose (BC) has provided significant conductivity and cost benefits. However, this combination has led to a reduction in mechanical properties, particularly in terms of elongation at break and tensile strength. This study investigated the enhancement of BC/PPy composite films by incorporating polyvinyl alcohol (PVA). The resulting BC/PPy/PVA films demonstrated improvements in flexibility, tensile strength and thermal stability. Specifically, with 7 % PVA, the flexible films exhibited remarkable enhancements: tensile strength increased from 11.01 MPa (for BC/PPy) to 25.27 MPa and elongation at break rose from 5.81 % to 11.54 %. Additionally, the electrical conductivity of the BC/PPy/PVA films with a resistance of 38.5 Ω, surpassed that of the BC/PPy films. Furthermore, the equilibrium swelling water absorption rates of BC/PPy and BC/PPy/PVA films were 30.6 % and 81.4 %, respectively, with corresponding resistances of 530 Ω and 540 Ω. The variation in resistance between the dry and swollen states of the BC/PPy/PVA flexible conductive film resulted in differences in the brightness of the small light bulb. These findings highlighted the synergistic effects of PVA within the BC/PPy matrix, presenting a promising avenue for developing high-performance conductive materials suitable for flexible electronics and wearable devices.

Physicochemical properties of bacterial cellulose from a strain of Komagataeibacter intermedius and analytical studies on its application

A high bacterial cellulose (BC) producing Komagataeibacter intermedius (KEI6 strain) was isolated from water kefir grains in Xinjiang, China. Under optimized culture conditions, the KEI6 strain was able to produce BC (KEI6-BC) up to 7.03 g/L dry weight. In this study, the rheological properties, hydrophilicity, molar mass, and specific surface area of KEI6-BC were systematically evaluated and characterized by three different drying treatments (freeze-drying, drying at 50 °C, and high-pressure homogenization). The results showed that KEI6-BC has a storage modulus of 104 Pa and a weight average molecular weight of 4.19×105 g/mol, which exhibits a randomly curled conformational polymer structure. Interestingly, freeze-dried treated KEI6-BC exhibited a highly uniform fiber distribution as well as good functional group retention, crystallinity, and thermal stability. In addition, we used freeze-dried KEI6-BC as a carrier to load ampicillin sodium and evaluated its antibacterial activity. It was found that freeze-dried KEI6-BC was promising as a carrier for slow drug release as well as exhibited good antibacterial activity after drug loading, demonstrating its great potential as an efficient antibacterial composite film.

Bacterial cellulose aerogels with sensitive indication and high adsorption capacity for indoor formaldehyde removal

Bacterial cellulose aerogels with sensitive indication and high adsorption capacity for indoor formaldehyde removal

Navigating the bacterial cellulose alternative substrates landscape: a bibliometric study and thematic analysis

Navigating the bacterial cellulose alternative substrates landscape: a bibliometric study and thematic analysis

An Asymmetric Bacterial Cellulose Membrane Incorporating CuPt Nanozymes and Curcumin for Accelerating Wound Healing.

Damaged skin compromises its ability to effectively prevent the invasion of harmful bacteria into the tissue, leading to bacterial infection of the wound and hindering the healing process. To address this challenge, we have developed a multifunctional asymmetric wound dressing (CuPt-Cur-ABC) that effectively addresses the lack of bactericidal activity and the release of active ingredients in conventional bacterial cellulose (BC), which can be employed to create a barrier of defense between the wound and its surrounding environment. Compared with BC, asymmetric bacterial cellulose (ABC) used starch as a pore-causing agent, forming holes of different sizes at the top and bottom, which enhanced the ability of ABC to load and moderate-release drugs. First, as-synthesized CuPt nanozymes with an octopod nanoframe structure had multiple enzymatic activities including peroxidase-like, catalase-like, and glutathione peroxidase-like activities. Then, CuPt and curcumin (Cur) were loaded into ABC under ultrasound. Under 808 nm laser irradiation, the nanocomposites possessed good photothermal properties. So the photothermal therapy combined with chemodynamic therapy and inherent antibacterial performance of Cur achieved 99.3% and 99.6% in vitro bactericidal efficacy against Staphylococcus aureus and Escherichia coli, respectively. Moderate release of Cur can clear the excess reactive oxygen species and promote the polarization of macrophages toward the M2 type. In vivo experiments additionally confirmed that the constructed wound dressing achieved multiple functions, including effective antibacterial activity, reversing the inflammatory microenvironment, and promoting wound healing.

Electrochemical Exfoliation of Large Antioxidative MXene Flakes for Polymeric Fire Safety.

Large-size MXene flakes have drawn growing attention due to their fascinating properties, which inevitably suffer from the low yield and weak oxidation resistance. Herein, an electrochemical exfoliation approach is proposed to achieve a high recording yield of 87% for preparing large antioxidative MXene flakes with an average lateral size of 8.3µm, which combines the etching, electrolyte intercalation, interlay expansion, and short-time sonication. Moreover, the MXene flakes can keep stable for over three months in the presence of water and oxygen, and even have good stability over 500°C under an air atmosphere, ascribed to the protection of the surface electrolyte layer. Combined with bacterial cellulose, the MXene can serve as an intelligent resistance-type sensor for contact/non-contact fire alarm, and further integrate with IoT for remote fire detection and warning within 1s. In addition, the MXene significantly improves the flame-retardant properties of indoor textiles and household materials, owing to the large thermostable 2D barriers to restrain heat and mass transfer. This work establishes an innovative and efficient method to prepare the large antioxidative MXene flakes in high yield for practical usage and extends its application to polymeric fire safety.

Structural and Viscoelastic Properties of Bacterial Cellulose Composites: Implications for Prosthetics.

This study investigates the morphological, mechanical, and viscoelastic properties of bacterial cellulose (BC) hydrogels synthesized by the microbial consortium Medusomyces gisevii. BC gel films were produced under static (S) or bioreactor (BioR) conditions. Additionally, an anisotropic sandwich-like composite BC film was developed and tested, consisting of a rehydrated (S-RDH) BC film synthesized under static conditions, placed between two BioR-derived BC layers. Sample characterization was performed using scanning electron microscopy (SEM), atomic force microscopy (AFM), rheometry, and uniaxial stretching tests. To our knowledge, this is the first study to combine uniaxial and rheological tests for BC gels. AFM and SEM revealed that the organization of BC fibrils (80±20 nm in diameter) was similar to that of collagen fibers (96±31 nm) found in human dura mater, suggesting potential implications for neurosurgical practice. Stretching tests demonstrated that the drying and rehydration of BC films resulted in a 2- to 8-fold increase in rigidity compared to other samples. This trend was consistent across both small and large deformations, regardless of direction. Mechanically, the composite (BioR+S-RDH) outperformed BC hydrogels synthesized under static and bioreactor conditions by approx. 26%. The composite material (BioR+S-RDH) exhibited greater anisotropy in the stretching tests compared to S-RDH, but less than the BioR-derived hydrogels, which had anisotropy coefficients ranging from 1.29 to 2.03. BioR+S-RDH also demonstrated the most consistent viscoelastic behavior, indicating its suitability for withstanding shear stress and potential use in prosthetic applications. These findings should provide opportunities for further research and medical applications.

Biomass‐based crosslinked composite anion exchange membranes using bacterial cellulose template towards enhanced ionic conductivity and alkaline stability

AbstractA balanced relationship among ionic conductivity, mechanical properties and alkaline stability of anion exchange membranes (AEMs) is essential for their practical application in fuel cells. Herein, a porous substrate (BC@LDH) with hierarchical structure was constructed using natural bacterial cellulose (BC) as a template and then in situ grew inorganic hydroxide ion conductor (layered double hydroxide, LDH). The membrane was fabricated via a filling together with sol–gel crosslinking strategy after impregnating an ionomer containing both quaternary ammonium and hydroxyl groups into the porous substrate and then crosslinked by organosiloxane. Due to the synergistic enhancement effect of BC, LDH and cross‐linking, the obtained membrane exhibited a tensile strength of 47.48 MPa that was 88.3% higher than that of the pure ionomer membrane, and showed an ionic conductivity of 70.7 mS cm−1 (80°C) which benefited from the introduction of ionic conductor LDH. More importantly, its alkaline stability was significantly improved and the residual conductivity ratio was still as high as 81.5% even after hot alkali treatment for 580 h. The direct methanol fuel cell assembled with this membrane exhibited a peak power density of 13.6 mW cm−2 with an open‐circuit voltage of 0.72 V, indicating its potential application in biomass‐based AEMs for fuel cells.Highlights Hierarchical porous substrate comprising LDHs anchored BC fiber was prepared. LDH@BC served as a reinforcing substrate and an ion transport medium. The crosslinked membrane showed significantly improved alkaline stability. The membrane had high ionic conductivity and mechanical strength. Providing a new way to design biomass‐based AEMs with high performance.

Asymmetric dot-patterned wettable and antibacterial wound dressings from bacterial cellulose–alginate composites coated with stearic acid-modified ZnO/chitosan/AgNPs

Asymmetric dot-patterned wettable and antibacterial wound dressings from bacterial cellulose–alginate composites coated with stearic acid-modified ZnO/chitosan/AgNPs

Green Synthesis of Nanoparticle-Loaded Bacterial Cellulose Membranes with Antibacterial Properties

The current work proposes the development of composite membranes based on bacterial cellulose (BC) loaded with silver (Ag) and zinc oxide (ZnO) nanostructures by in situ impregnation. The research involves the production and purification of BC, followed by its loading with different types of phases with the help of different precipitating solutions, turmeric extract (green synthesis) and ammonia (classic route). Additionally, the combination of both antibacterial agents into a single BC matrix to valorise the benefits of each, proposing a novel BC-Ag-ZnO composite with distinct characteristics, was explored. Overall, the synthesis was marked by colour changes from the light beige of the BC membrane to dark brown, dark orange and dark green for BC-Ag, BC-ZnO and BC-Ag-ZnO samples, which is proof of successful composites formation. The results proved that the antibacterial phases are attached as nanoparticles or nanosheets on BC fibres, with Ag being in a crystalline state, while ZnO showed a rather amorphous structure. Regarding the antibacterial efficiency, the BC-ZnO composite obtained by employing two precipitating solutions turned out to be the best material against both tested Gram-negative and Gram-positive bacterial strains.

Correction: Production of bacterial cellulose by Komagataeibacter xylinus: biochemistry, synthesis and applications

Correction: Production of bacterial cellulose by Komagataeibacter xylinus: biochemistry, synthesis and applications

Ultra‐High Radial Elastic Aerogel Fibers for Thermal Insulation Textile

AbstractWhen nanoporous aerogels with excellent thermal insulation performance are processed into 1D fibers, they have great potential for application in the field of personal thermal management. However, coping with the impact of external forces, especially radial extrusion, and maintaining the macro morphology and microstructure of aerogels during use are remaining issues. To address these challenges, this study proposes a method that uses ultrafine and ultra‐highly entangled bacterial cellulose nanofibers as the basis to achieve high radial elasticity by forming an isomorphic coating of rigid silica on the soft gel skeleton of aerogel fibers. The obtained aerogel fibers can achieve an elastic recovery of 88% over 50 compression cycles under 90% strain, and they can be knotted, woven into textiles, and are washable. This strategy improves the radial compression resistance of aerogel fibers, providing rich possibilities for the development of aerogel fibers with excellent mechanical properties.

Characteristics of deep-sea microbial cellulases: key determinants of the ultimate fate of plant biomass on Earth

Land plants, especially those with significant woody biomass, represent the largest source of biomass on Earth, making the biodegradation of lignocellulosic materials critical to understanding the global carbon cycle. Cellulose, a major component of lignocellulose, is notoriously resistant to degradation due to its highly crystalline structure. While the degradation of cellulose by terrestrial microbes has been extensively studied, the mechanisms of cellulose degradation in deep-sea environments remain largely unexplored. The deep-sea ecosystem depends on organic matter, such as cellulose, that is synthesized in terrestrial environments and surface waters and descends to the deep sea. Recent studies suggest that a significant amount of cellulose is likely to reach the deep sea. Here, we present an in-depth study of cellulases from a novel deep-sea γ-proteobacterial strain TOYAMA8, isolated from Toyama Bay, Japan, using Surface Pitting Observation Technology (SPOT), a highly sensitive assay for enzymatic cellulose hydrolysis. The cellulases of strain TOYAMA8 show similarities to those of a previously reported deep-sea cellulolytic microbe, Marinagarivorans cellulosilyticus strain GE09. Genomic and transcriptomic analyses of these strains reveal novel cellulase genes and mechanisms that differ from terrestrial counterparts, shedding light on the unique adaptations of deep-sea microbes to recalcitrant biomass. In particular, these strains produce high-molecular-weight cellulases with unique domain architectures, likely optimized for membrane anchoring, which prevents enzyme diffusion and ensures efficient localized activity. Our findings provide critical insights into the microbial cellulose degradation in the deep sea, highlighting its role in the fate of organic carbon and the potential for biotechnological applications in biorefineries.

MXene/Bacterial Cellulose Hybrid Materials for Sustainable Soft Electronics.

This work evaluated bacterial cellulose (BC) as a possible biodegradable soft electronics substrate in comparison to polyethylene terephthalate (PET), while also focusing on evaluating hybrid MXene/BC material as potential flexible electronic sensor. Material characterization studies revealed that the BC material structure consists of nanofibers with diameters ranging from 70 to 140 nm, stacked layer-by-layer. BC samples produced are sensitive to post-treatment with isopropanol resulting in a change of structural and mechanical properties. The viscoelastic properties of the BC substrates have been studied experimentally in comparison with the PET film. Aged BC substrate showcased similar viscoelastic properties stability, while exhibiting better properties above 70 °C, with total storage modulus change of -15% and loss modulus change of 21%. MXenes prepared using the Minimally Intensive Layer Delamination (MILD) method were screen-printed onto BC substrates and PET films to form MXene/BC (MX/BC) and MXene/PET (MX/PET) devices. The electrical properties results showcased different resistive behavior on both BC and PET substrate samples with different impedance moduli. MX/PET presented lower sheet resistance of around 156 Ω·sq-1, while MX/BC was 2733 Ω·sq-1. Finally, the MX/BC and MX/PET devices were subjected to repeatable quasi-static load tests and the piezoresistive sensing behavior of the devices has been reported.

Understanding the Role of Surface Chemistry in Nanocellulose Kink Formation: A Case Study of TEMPO-Mediated Oxidation.

This study found that the sources of cellulose have a significant effect on the parameters related to the kinks present in nanocellulose. During nanocellulose preparation, 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO)-mediated oxidation induced partial depolymerization on whole cellulose and made the amorphous regions more susceptible to consequent mechanical treatment irrespective of cellulose sources. However, plant cellulose microfibrils were prone to break into shorter nanocellulose with fewer kinks, while bacterial and tunicate cellulose were more likely to bend rather than break, thus leading to the generation of more kinks. The kinks did not show significant effects on the size, crystallinity index, and thermal properties of nanocellulose for each cellulose source, though the kink numbers were positively related to the mechanical performance of nanocellulose. Collectively, this study elucidated the kink formation mechanisms and clarified the effects of kinks on nanocellulose performance, thus providing new insights into understanding the source and behaviors of microdefects present in nanocellulose.

Low-cost bacterial cellulose production from agricultural waste for antibacterial applications

Various carbon sources can be utilized for the biosynthesis of bacterial cellulose (BC), with agricultural wastes being explored as sustainable options. In this study, glucose was extracted from bamboo dust via mild acid hydrolysis to prepare a modified medium combining extracted glucose with Hestrin-Schramm (HS) medium for BC biosynthesis using Acetobacter xylinus NCIM 2526. Chitosan, a biopolymer, was incorporated into the BC synthesis medium at concentrations of 0.2%, 0.6%, and 1% (w/v) after 2 days of shaking incubation, producing chitosan-incorporated BC membranes through in situ synthesis. Fourier transform infrared (FTIR) spectroscopy confirmed cellulose in the BC produced from the modified medium and chitosan in BC membranes with 0.2% and 0.6% (w/v) chitosan. Changes in physical and crystalline morphology were further characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. The purity of cellulose was validated through chemical solubility tests, while energy-dispersive X-ray (EDX) analysis confirmed the presence of chitosan in the BC membranes. The average yields were 5.8 ± 0.21 g/l for pure BC, 5.2 ± 0.21 g/l for BC with 0.2% (w/v) chitosan, and 4.6 ± 0.21 g/l for BC with 0.6% (w/v) chitosan after 7 days. The medium with 1% (w/v) chitosan did not produce BC membranes. BC synthesized with 0.2% chitosan exhibited similar physical and chemical properties to pure BC and demonstrated good antimicrobial properties, suggesting its potential use in bandages and wound dressings.

Preparation of insoluble bacterial cellulose xanthate for copper ion removal

Preparation of insoluble bacterial cellulose xanthate for copper ion removal