Bacterial Cellulose Pellicles Research Articles

Enhanced rheological properties and conductivity of bacterial cellulose hydrogels and aerogels through complexation with metal ions and PEDOT/PSS

Bacterial cellulose (BC) based hybrid hydrogels and aerogels have been fabricated by reformatting BC pellicles. BC pellicles are formed by tight fibrillar networks making it challenging to incorporate other materials to form hybrids or composites. In this study, BC pellicles produced from two Acetobacteracea family members are disintegrated into individual nanofibrils via TEMPO-mediated oxidation. The individualized BC nanofibrils about tens of microns in length and 20–50 nm in width are well-dispersed in water with crystallinity and birefringence of cellulose I. These BC nanofibril dispersions are non-Newtonian fluid. Upon complexation with 0.75 mmol/g of Fe3+, the formed BC nanofibril hydrogels display 17-fold increase in storage moduli. Composite aerogels formed by complexation with conductive polymer PEDOT/PSS show characteristics of a non-Hookean foam material with conductivity value of up to 0.86 S/cm for cellulose density of 4.2 mg/cm2.

Aerogel from Sustainably Grown Bacterial Cellulose Pellicles as a Thermally Insulative Film for Building Envelopes.

Improving building energy performance requires the development of new highly insulative materials. An affordable retrofitting solution comprising a thin film could improve the resistance to heat flow in both residential and commercial buildings and reduce overall energy consumption. Here, we propose cellulose aerogel films formed from pellicles produced by the bacteria Gluconacetobacter hansenii as insulation materials. We studied the impact of the density and nanostructure on the aerogels' thermal properties. A thermal conductivity as low as 13 mW/(K·m) was measured for native pellicle-based aerogels that were dried as-is with minimal post-treatment. The use of waste from the beer brewing industry as a solution to grow the pellicle maintained the cellulose yield obtained with standard Hestrin-Schramm media, making our product more affordable and sustainable. In the future, our work can be extended through further diversification of food wastes as the substrate sources, facilitating higher potential production and larger applications.

Morphology and structure of bacterial cellulose film after ionic liquid treatment

Chemical treatment like ionic liquid is known as a green solvent had developed to improve the compatibility of bacterial cellulose in many composite applications. This study aimed to know the influence of treatment using the ionic liquid on the morphology and structure of bacterial cellulose film (BCF). The methods used a BCF made of pineapples peels waste. Pellicle, as fermentation product as long as 14 days, washed by distilled water then immersed to an ionic liquid solution such as 1-Butyl-3-methylimidazolium chloride (BmimCl) for 2 h with concentrations of 0%, 2.5%, 5.0%, and 7.5%. Treated BC pellicle was dried in an oven for 6 h for obtaining bacterial cellulose film (BCF) then observed by XRD and SEM. The result showed that the treatment using BmimCl change the surface morphology and structure of of BCF. BmimCl solution with a concentration of 5.0% and 7.5% show cause some holes in the surface of bacterial cellulose film. BmimCl solution treatment changed the structure of BCF, indicated by the increasing the peak intensity of diffractogram at a diffraction angle of 14.4° and 22.7°. Crystalline content after treatment by BmimCl with concentrations of 0%, 2.5%, 5.0%, and 7.5% were 73.85%, 73.50%, 71.33%, and 72.81%, respectively.

Cellulose nanocomposites reinforced with bacterial cellulose sheets prepared from pristine and disintegrated pellicle

BC sheets can be prepared in two forms: direct press-drying of the as-synthesised BC pellicle or disintegrating the BC pellicle to create a homogenous BC-in-water suspension prior to producing the BC sheet. We found that BC sheet prepared from direct press-drying of pristine pellicle was more homogeneous due to its better BC network formation and possessed higher specific surface area (46 g m−2), better resin impregnation and mechanical properties compared to its disintegrated pellicle counterpart (21 g m−2). BC-poly(acrylated epoxidised soybean oil) (polyAESO) nanocomposites consisting of BC sheet prepared from pristine pellicle was optically transparent whilst BC-polyAEO nanocomposites consisting of BC sheet prepared from disintegrated pellicle was opaque. Whilst the tensile properties of BC-polyAESO nanocomposites from pristine pellicle were higher, the fracture toughness of BC-polyAESO composite consisting of BC sheet from disintegrated pellicle was better. The lack of resin impregnation in BC-polyAESO from disintegrated pellicle led to a laminated structure, which utilised the fracture toughness of BC sheet effectively.

Interaction of silver sulfadiazine wıth bacterial cellulose via ex-situ modification method as an alternative diabetic wound healing

Abstract The conventional silver dressing raises growing concerns amongst clinicians that this dressing could lead to increased morbidity and prolonged treatment period relating to uncontrolled wound bioburden. Bacterial cellulose (BC) is a good candidate of alternative treatment method for wound healing but it lacks of antimicrobial activity. Hence, this research was aimed to enhance the efficiency of wound healing by incorporating silver sulfadiazine (SSD) to the BC. BC pellicles was produced through static fermentation process in Hestrin Schramn medium. The BC-SSD membranes was prepared through ex-situ modification method by immersing BC pellicles in various concentration of SSD solution (0.2–1.0 %v/w) for 24 h. The properties of BC-SSD produced was characterized by SEM, FTIR, tensile strength, swelling test, release kinetic and antimicrobial activity. The presence of silver in the BC-SSD membrane was confirmed by the presence of sulfonamide, a basic structure of silver sulfadiazinee from the peaks obtained in FTIR spectrum. In addition, the tensile strength of the BC-SSD membranes increase proportionately with SSD concentration incorporated to the BC. The BC also have the capability of absorbing alkaline better compared to the acidic absorption. The release kinetic study shows that silver ions were efficiently released in 24 h and gradually reduced for the next 72 h. Ultimately, the BC-SSD had pronounced antibacterial activity against Escherichia coli and Pseudomonas eruginosa, the most commonly bacteria found in diabetic foot ulcer (DFU) which suggest its capability as alternative wound dressing for DFU.

Application of bacterial cellulose–silver nanoprism composite for detoxification of endosulfan and inactivation of Escherichia coli cells

This study demonstrates the suitability of a bacterial cellulose–silver nanoprism composite for detoxification of endosulfan and disinfection of water spiked with Escherichia coli cells. Nanoprisms were synthesized using sodium borohydride reduction in combination with hydrogen peroxide-assisted etching. Characterization of nanoparticles using absorption spectroscopy and electron microscopy revealed the presence of silver nanoprisms ranging from 7 to 37 nm. Analysis using inductively coupled plasma atomic emission spectroscopy revealed the successful doping of silver nanoprisms onto bacterial cellulose pellicles through overnight immersion of the polymer in the colloidal solution containing free nanoparticles. The bacterial cellulose–silver nanoprism composite (2.5 mg of Ag0/g of bacterial cellulose) along with Mg0 system removed > 99% of 10 mg L−1 of endosulfan after 45 min of reaction by transforming into its end product, bicyclo-hept-5-ene-2,3-diol. The BC–Ag0 composite exhibited biocidal activity against E. coli (3 × 104 CFU mL−1), and the extent of reduction was ~ 99% after 65 min of contact. The BC–Ag0 composite could be reused successfully for 5–6 cycles of degradation of endosulfan with an efficacy of ~ 86% and 6–7 cycles of disinfection with > 99% antimicrobial activity against E. coli. The leaching of silver was below the permissible limit (0.1 mg L−1). Results obtained from this study suggest that the bacterial cellulose–silver nanoprism composite could be used for remediation of water contaminated with chlorinated pesticides such as endosulfan and infectious bacteria. It can be concluded that impregnation of silver nanoprisms on bacterial cellulose encourages reuse of nanoparticles, reduces environmental risks and makes the process more economical.

Bacterial Cellulose production by K. saccharivorans BC1 strain using crude distillery effluent as cheap and cost effective nutrient medium

Bacterial Cellulose (BC), a valuable biopolymer gaining importance over the past few decades due to its remarkable properties and applications. In this study, crude distillery effluent having a high COD value of 87,433 mg/L was used to produce Bacterial Cellulose under static fermentation by Komagataeibacter saccharivorans, a novel isolated bacterial strain. 1.24 g/L of cellulose production was noted after eight days along with 23.6% reduction in COD value. The BC pellicle was purified, lyophilized and stored. Further, the lyophilized BC pellicle was subjected to characterization techniques such as SEM, ATR-FTIR, XRD, NMR and TLC. Morphological analysis revealed that cellulose fibers were dense with higher porosity and an average fiber width of 60 nm. FTIR depicted similar functional groups as that of BC-HS medium. TLC of the biopolymer was performed to evaluate its purity. X-ray diffraction and 13C NMR studies gave more insights about the crystalline and the amorphous regions; the synthesized polymer exhibited 80.2% as crystallinity and crystallite size of 8.36. Hence, the present study demonstrates that distillery effluent waters could be effectively reused as production medium fulfilling two objectives namely one reducing COD and making the effluent safe for disposal and two to produce a value-added product.

Development and Characterization of Bacterial Cellulose Reinforced with Natural Rubber.

Films of bacterial cellulose (BC) reinforced by natural rubber (NR) with remarkably high mechanical strength were developed by combining the prominent mechanical properties of multilayer BC nanofibrous structural networks and the high elastic hydrocarbon polymer of NR. BC pellicle was immersed in a diluted NR latex (NRL) suspension in the presence of ethanol aqueous solution. Effects of NRL concentrations (0.5%–10% dry rubber content, DRC) and immersion temperatures (30–70 °C) on the film characteristics were studied. It was revealed that the combination of nanocellulose fibrous networks and NR polymer provided a synergistic effect on the mechanical properties of NR–BC films. In comparison with BC films, the tensile strength and elongation at break of the NR–BC films were considerably improved ~4-fold. The NR–BC films also exhibited improved water resistance over that of BC films and possessed a high resistance to non-polar solvents such as toluene. NR–BC films were biodegradable and could be degraded completely within 5–6 weeks in soil.

Comparative study of plant and bacterial cellulose pellicles regenerated from dissolved states

Bacterial cellulose (BC), representing the highly purified form of cellulose, possesses better nanofibrous morphology and superior mechanical properties than plant cellulose (PC). However, the regeneration process, which produces intermediate structures, significantly alters the original properties of native cellulose and result in varied structural and physico-mechanical features. Therefore, it is important to estimate the degree of variations in the structures and properties of both PC and BC during their regeneration. Herein, we conducted a detailed comparative study by dissolving BC and PC in N-methylmorpholine N-oxide (NMMO) and synthesizing their regenerated gels, namely regenerated bacterial cellulose (RBC) and regenerated plant cellulose (RPC), respectively. The structural features of BC, PC, RBC, and RPC were comparatively evaluated via field-emission scanning electron microscopy, X-ray diffraction, porosity analyses, as well as analyzed their mechanical, thermal, and liquid-holding capabilities. The results showed inferior mechanical, thermal, and crystalline features of RBC and RPC to their respective counterparts. However, RBC showed better porosity, water absorption capability, and water retention time than RPC. The overall mechanical, thermal, and physiological features of RBC were better than those of RPC. These findings may facilitate the use of RBC in composite synthesis for various applications.

Characterization of CuO-bacterial cellulose nanohybrids fabricated by in-situ and ex-situ impregnation methods

The aim of this research was to fabricate CuO-bacterial cellulose (BC) nanohybrids by two in-situ synthesis methods including sonochemical and precipitation methods. The ex-situ synthesized nanohybrid was also prepared by immersing BC pellicles in commercial CuO dispersion. FT-IR analysis confirmed the formation of real nanohybrid by occurring new interactions between CuO-NPs and BC. XRD results approved no disruption effect of nanohybrid formation on the crystallinity index of BC nanofibers. FE-SEM results indicated the formation of small sized NPs attached to the inner space of BC network at in-situ synthesized nanohybrids. But agglomerated NPs precipitated on the surface of BC layer was observed for ex-situ synthesized sample. In spite of higher loading capacity of ex-situ method, the in-situ synthesized nanohybrids exhibited lower release rate of NPs into the water. The antibacterial activity of ex-situ synthesized nanohybrid against S.aureus and E.coli bacteria was more than both of in-situ synthesized samples.

Fabrication and characterization of novel bacterial cellulose/alginate/gelatin biocomposite film

Hydrogels from bacterial, algal, and animal cells—bacterial cellulose (BC), alginate, and gelatin, respectively—were combined to fabricate a biocomposite film (BCAGG) via an eco-friendly casting technique. In addition, glycerol was added as a plasticizer to improve the elasticity and water absorption capacity of the film. In this study, BC pellicles were simply deconstructed into fibrils suspension and then reconstructed into films with a supplement of alginate, gelatin and glycerol. The physical appearance of fabricated films resembled native BC but possessed improved ductility, enhanced flexibility, higher water uptake ability and better biocompatibility. The film was found to resist tearing under suture pullout strength in a hydrated state. In vitro cytotoxicity tests showed that the film was cytocompatible. A cell study using a human keratinocyte culture demonstrated enhanced cell adhesion, spreading, and proliferation on the BCAGG film compared with BC/alginate film. The BCAGG film therefore has significant potential for use in biomedical applications, particularly in dermal treatment, skin tissue regeneration, and wound healing.

Enhanced mechanical properties of bacterial cellulose nanocomposites produced by co-culturing Gluconacetobacter hansenii and Escherichia coli under static conditions

Including additives in the culture media during bacterial cellulose (BC) biosynthesis is a traditional method to produce BC-based nanocomposites. This study examines a novel fermentation process, which is to co-culture Gluconacetobacter hansenii (G. hansenii) with Escherichia coli (E. coli) under static conditions, to produce BC pellicles with enhanced mechanical properties. The mannose-rich exopolysaccharides (EPS) synthesized by E. coli were incorporated into the BC network and affected the aggregation of co-crystallized microfibrils without significantly changing the crystal sizes of BC. When co-culturing G. hansenii ATCC 23769 with E. coli ATCC 700728, which produced a low concentration of EPS at 3.3 ± 0.7 mg/L, the BC pellicles exhibited a Young’s modulus of 4,874 ± 1144 MPa and a stress at break of 80.7 ± 21.1 MPa, which are 81.9% and 79.3% higher than those of pure BC, respectively. The growth dynamics of the two co-cultured strains suggested that the production of BC and EPS were enhanced through co-culturing fermentation.

Bacterial Cellulose: A Versatile Chiral Host for Circularly Polarized Luminescence.

Materials capable of circularly polarized luminescence (CPL) have attracted considerable attention for their promising potential applications. Bacterial cellulose (BC) was characterized as having a stable right-handed twist, which makes it a potential chiral host to endow luminophores with CPL. Then, the CPL-active BC composite film was constructed by simply impregnating bacterial cellulose pellicles with dilute aqueous solutions of luminophores (rhodamine B, carbon dots, polymer dots) and drying under ambient conditions. Simple encapsulation of luminophores renders BC with circularly polarized luminescence with a dissymmetry factor of up to 0.03. The multiple chiral centers of bacterial cellulose provide a primary asymmetric environment that can be further modulated by supramolecular chemistry, which is responsible for its circular polarization ability. We further demonstrate that commercial grade paper may endow luminophores with CPL activity, which reifies the universality of the method.

Comparative Study of Bacterial Cellulose Film Dried Using Microwave and Air Convection Heating

An investigation was conducted to analyze and compare the properties of bacterial cellulose (BC) films dried using microwave and air convection heating. Prior to the drying process, 90% of the water content inside the BC pellicles was removed through vacuum filtration. After that, the required drying time was only 3-5 min using microwave heating, 95% shorter than that observed for air convection heating. The properties of the BC sheets were characterized by Fourier transform infrared (FTIR), X-ray diffractometer (XRD), color difference meter, and tensile tester machine. The results showed that the structure of the BC films was the same for the BC films dried by microwave and air convection heating, i.e. cellulose I, as observed from FTIR spectra and XRD diagrams. Moreover, their color (L*, a*, and b* values) and mechanical properties were also almost identical. However, a slightly lower crystallinity and a higher swelling degree were observed for the BC film dried using microwave heating. These results suggest that microwave heating could be an alternative method of drying BC pellicles in order to shorten the processing time and reduce energy consumption when compared to air convection heating.

Physical, morphological, antimicrobial and release properties of novel MgO-bacterial cellulose nanohybrids prepared by in-situ and ex-situ methods.

MgO-bacterial cellulose (BC) nanohybrids were fabricated by in-situ synthesis of nanoparticles (NPs) within BC network via two methods (the sonochemical and wet chemical). The ex-situ synthesized nanohybrid was prepared by immersing BC pellicles in the commercial MgO dispersion. The occurrence of new interactions between MgO-NPs and nanofibers was approved by Fourier transform infrared spectroscopy (FT-IR) spectra. X-ray diffraction (XRD) results indicated that the crystallinity index of nanofibers decreased after the formation of nanohybrid by the sonochemical in-situ method. The results of the field emission scanning electron microscopy (FE-SEM) indicated the formation of the small-sized NPs attached to the inner space of BC network at the in-situ synthesized nanohybrids. However, the agglomerated NPs precipitated on the surface of BC layer were observed for the ex-situ synthesized sample. The loading capacity of the ex-situ method was higher than that of the in-situ methods; but after 24 h, MgO releasing for in-situ and ex-situ synthesized nanohybrids was recorded about 16% and 28%, respectively. The antibacterial activity of the ex-situ synthesized nanohybrid against S. aureus and E. coli bacteria was more than those of both in-situ synthesized samples.

Structural and rheological characterization of bacterial cellulose gels obtained from Gluconacetobacter genus

This study explores the structural and rheological properties of bacterial cellulose gels (pellicles) produced by bacteria isolated from several kinds of fruits. The three bacteria isolated were identified as Gluconacetobacter sp. and two strains of Gluconacetobacter hansenii. The obtained pellicles were analyzed by Fourier transform infrared spectroscopy, solid-state 13C nuclear magnetic resonance, and X-ray diffraction. On the basis of the structural characterization, the Iα content was approximately 60%, the extent of crystallization was in the range 57–67%, and the crystal sizes were in the range 5.23–5.68 nm. Morphology of the pellicles was observed by scanning electron microscopy. Rheological properties of the pellicles were evaluated using a rheometer. The widths of cellulose fibers and rheological properties were different among the pellicles produced by the mentioned bacteria. Overall, the results obtained in this study indicated that the rheological properties of the BC pellicles were strongly influenced by the network structure of the cellulose fibers rather than by fiber concentrations. Thus, we obtained useful information related to BC pellicle for both basic research as well as for the determination of their potential for application in industries concerning food, cosmetics, and medicine.

The investigation of producing bacterial cellulose fibres through hand-spun

Nanocellulose fibres can be hand-spun from different intermediate states, such as nanocellulose paper and filter cake, which are made from the BC suspension as well as wet pellicle (WP) and dry pellicle (DP) from BC pellicles. In this study, it can be concluded that increasing the hanging weight can increase the Young’s modulus and the tensile strength of fibres. Nanofibres produced from BC pellicles as raw material have better performance than those made from BC suspension. The best properties obtained from the fibres produced from wet pellicles and suspended to a 100g hanging weight upon drying are Young’s modulus (33.8 GPa), tensile strength (610 MPa) and elongation at break (3.6%).

Characterization of Bacterial Cellulose From Oil Palm Shoot Juices and Coconut Juice/Poly(ethylene glycol) Biocomposite

A new biocomposite was preformed between bacterial cellulose (BC) pellicle and polyethylene glycol (PEG) at different concentrations (0%, 5, 10%, 15% and 20%) and different molecular weight (600, 1000 and 2000). The structure... | Find, read and cite all the research you need on Tech Science Press

Evaluation of inoculum size and fermentation period for bacterial cellulose production from sago liquid waste

The production of bacterial cellulose (BC) from sago liquid waste was examined. In this study, the influence of different inoculum size (5, 10, 15, 20, 25 and 30%) and fermentation period (5, 10, 15 and 20 days) for BC production were evaluated. The yield of BC was examined based on dry weight. The growth of bacteria in the fermentation medium was enumerated using pour plate technique. The profile of viable bacterial cell Acetobacter xylinum LKN6 on the BC pellicles was analyzed by scanning electron microscopy. The results showed that the inoculum size and fermentation period had an effect on bacterial cellulose production from sago liquid waste. The inoculum size of 25% (v/v) produced highest yield of bacterial cellulose (13.85 g/L). The yield of BC increased with fermentation time and the optimum fermentation period was 15 days. The pattern of bacterial growth was related to BC production. The cell of A. xylinum LKN6 embedded in the bacterial cellulose pellicle and it was formed fibril cellulose secreted through bacteria cell wall. Therefore, the factors of inoculum size and incubation period affected production of bacterial cellulose from sago liquid waste.

Engineered cell-to-cell signalling within growing bacterial cellulose pellicles.

SummaryBacterial cellulose is a strong and flexible biomaterial produced at high yields by Acetobacter species and has applications in health care, biotechnology and electronics. Naturally, bacterial cellulose grows as a large unstructured polymer network around the bacteria that produce it, and tools to enable these bacteria to respond to different locations are required to grow more complex structured materials. Here, we introduce engineered cell‐to‐cell communication into a bacterial cellulose‐producing strain of Komagataeibacter rhaeticus to enable different cells to detect their proximity within growing material and trigger differential gene expression in response. Using synthetic biology tools, we engineer Sender and Receiver strains of K. rhaeticus to produce and respond to the diffusible signalling molecule, acyl‐homoserine lactone. We demonstrate that communication can occur both within and between growing pellicles and use this in a boundary detection experiment, where spliced and joined pellicles sense and reveal their original boundary. This work sets the basis for synthetic cell‐to‐cell communication within bacterial cellulose and is an important step forward for pattern formation within engineered living materials.