Isolation and characteristics analysis of a novel high bacterial cellulose producing strain Gluconacetobacter intermedius CIs26

3D printing of bacterial cellulose for potential wound healing applications: Current trends and prospects

Several advances in skin tissue engineering have been made to restore skin damage, facilitating wound healing. Bacterial cellulose (BC), a naturally occurring polymer, has gained attention as a potential material in wound healing due to its unique physical and biological properties. In recent years, with the advent of 3D bio-printing technology, new avenues have opened for fabricating customized wound dressings and scaffolds for tissue engineering purposes. The existing literature in this field mainly focuses on the ways of modifications of bacterial cellulose to make it printable. Still, the applicability of 3D printed scaffolds for wound healing needs to be explored more. This review article focuses on the current research on using 3D-printed BC for skin regeneration, including its production methods and physical and biological properties, making it a better choice than traditional dressings. Furthermore, it also highlights the limitations and future directions for using BC in wound healing and tissue engineering applications. This review provides a comprehensive and up-to-date exploration of the applications of 3D-printed BC in wound healing, drawing insights from pre-existing studies and emphasizing patient compliance, clinical outcomes, and economic viability.

Functionalization of bacterial cellulose: Exploring diverse applications and biomedical innovations: A review

The demand for the functionalization of additive materials based on bacterial cellulose (BC) is currently high due to their potential applications across various sectors. The preparation of BC-based additive materials typically involves two approaches: in situ and ex situ. In situ modifications entail the incorporation of additive materials, such as soluble and dispersed substances, which are non-toxic and not essential for bacterial cell growth during the production process. However, these materials can impact the yield and self-assembly of BC. In contrast, ex situ modification occurs subsequent to the formation of BC, where the additive materials are not only adsorbed on the surface but also impregnated into the BC pellicle, while the BC slurry was homogenized with other additive materials and gelling agents to create composite films using the casting method. This review will primarily focus on the in situ and ex situ functionalization of BC then sheds light on the pivotal role of functionalized BC in advancing biomedical technologies, wound healing, tissue engineering, drug delivery, bone regeneration, and biosensors.

Efficient production of bacterial cellulose based composites using zein protein extracted from corn gluten meal

Corn gluten meal (CGM) which is a byproduct of corn wet milling is mainly used in animal and poultry feed. Due to its high protein content in CGM, it has been utilized for the extraction of zein protein which is the main hydrophobic protein present in the corn. The extracted zein protein was used along with bacterial cellulose that is highly pure, biocompatible, biodegradable, and generally regarded as safe for the preparation of composites that have better surface properties and applications. SEM analysis of the synthesized composite showed layering, incorporation of zein protein onto the surface of bacterial cellulose. XRD results showed there were no significant changes in the peak intensity due to the surface modification of BC membranes composites in comparison to pristine BC and TGA showed the thermostable characteristic of bacterial cellulose and are more capable of withstanding high temperature. Maximum production of bacterial cellulose was observed when corn gluten meal and zein protein were used as a cheap nitrogen sources for the production of bacterial cellulose along with other medium components. An increase of approximately 4.0 g/l of bacterial cellulose from 13.561 g/l to 17.83 g/l was observed when corn gluten meal and zein protein were used in the production medium. The prepared BC-based zein protein composites can be utilized for food packaging and storage applications.

Antibacterial Activity and Mechanism of Oxidized Bacterial Nanocellulose with Different Carboxyl Content

Oxidized bacterial nanocellulose (OBC) is reported to prevent microbial growth, but its antibacterial characteristics and mechanism are still unclear. Here, the antibacterial mechanism of OBC is explored by detecting and assessing the interaction of OBC with different carboxyl content on Staphylococcus aureus and Escherichia coli. The results show that OBC has strong antibacterial activity and antibiofilm activity against S. aureus and E. coli, which is positively correlated with the carboxyl content of OBC. After OBC treatment, the bacteria adhesion is inhibited and the cell membrane is destroyed leading to increased permeability. Further investigation reveals that the concentration of cyclic diguanosine monophosphate (c-di-GMP) that induced biofilm formation is significantly decreased to 1.81 pmol mg^-1 after OBC treatment. In addition, OBC inactivates mature biofilms, with inactivation rates up to 79.3%. This study suggests that OBC has excellent antibacterial and antiadhesion properties, which can increase the cell membrane permeability and inhibit c-di-GMP formation. In addition, OBC also has a strong inactivation effect on mature biofilm, which can be used as an effective antibiofilm agent.

Bacterial cellulose membrane combined with BMSCs promotes wound healing by activating the notch signaling pathway

Objective

The bacterial cellulose membrane (BCM) has been widely studied and applied as a new biomaterial for wound healing, but causes pain with frequent dressing changes. Local application of bone marrow mesenchymal stem cells (BMSCs) requires a niche. Furthermore, the effect and mechanism of the BCM combined with BMSCs have not been reported.

Methods

Morphological and chemical identifications of BCMs were investigated by porosity analyses, scanning electron microscopy, and Fourier-transform infrared spectroscopy. Biological wound dressings (BWDs) were prepared by the BCM in combination with BMSCs. The biological effects of BWDs on human dermal fibroblast (HDF) and VEGF-A in human vascular endothelial cells (HuVECs) were detected in vitro, and the effect of BWDs on acute wounds in mice was detected in vivo. Collagen and angiogenesis were evaluated through hematoxylin-eosin staining and Masson staining. The expressions of COL-1 and VEGF-A and the activation of the Notch signaling pathway in vivo and in vitro were detected by quantitative reverse-transcriptase polymerase chain reaction.

Results

The BCM had a nanoscale structure and provided a partial niche for the survival and proliferation of BMSCs. BWDs were successfully prepared and regulated the biological behaviors of wound healing-related cells in vitro and upregulated the expressions of COL-1 in HDF and VEGF-A in HuVECs. BWDs promoted wound healing by increasing collagen type I synthesis and angiogenesis in acute wounds in mice.

Conclusions

BWDs prepared by the combination of nanomaterial BCMs and BMSCs facilitated acute wound healing, which may be regulated by activating the Notch signaling pathway.

The Antimicrobial Effects of Bacterial Cellulose Produced by Komagataeibacter intermedius in Promoting Wound Healing in Diabetic Mice

As a conventional medical dressing, medical gauze does not adequately protect complex and hard-to-heal diabetic wounds and is likely to permit bacterial entry and infections. Therefore, it is necessary to develop novel dressings to promote wound healing in diabetic patients. Komagataeibacter intermedius was used to produce unmodified bacterial cellulose, which is rarely applied directly to diabetic wounds. The produced cellulose was evaluated for wound recovery rate, level of inflammation, epidermal histopathology, and antimicrobial activities in treated wounds. Diabetic mices' wounds treated with bacterial cellulose healed 1.63 times faster than those treated with gauze; the values for the skin indicators in bacterial cellulose treated wounds were more significant than those treated with gauze. Bacterial cellulose was more effective than gauze in promoting tissue proliferation with more complete epidermal layers and the formation of compact collagen in the histological examination. Moreover, wounds treated with bacterial cellulose alone had less water and glucose content than those treated with gauze; this led to an increase of 6.82 times in antimicrobial protection, lower levels of TNF-α and IL-6 (39.6% and 83.2%), and higher levels of IL-10 (2.07 times) than in mice wounds treated with gauze. The results show that bacterial cellulose produced using K. intermedius beneficially affects diabetic wound healing and creates a hygienic microenvironment by preventing inflammation. We suggest that bacterial cellulose can replace medical gauze as a wound dressing for diabetic patients.

Research progress of the biosynthetic strains and pathways of bacterial cellulose

Bacterial cellulose is a glucose biopolymer produced by microorganisms and widely used as a natural renewable and sustainable resource in the world. However, few bacterial cellulose-producing strains and low yield of cellulose greatly limited the development of bacterial cellulose. In this review, we summarized the 30 cellulose-producing bacteria reported so far, including the physiological functions and the metabolic synthesis mechanism of bacterial cellulose, and the involved three kinds of cellulose synthases (type I, type II, and type III), which are expected to provide a reference for the exploration of new cellulose-producing microbes.

Bacterial Cellulose: Production, Characterization, and Application as Antimicrobial Agent

Bacterial cellulose (BC) is recognized as a multifaceted, versatile biomaterial with abundant applications. Groups of microorganisms such as bacteria are accountable for BC synthesis through static or agitated fermentation processes in the presence of competent media. In comparison to static cultivation, agitated cultivation provides the maximum yield of the BC. A pure cellulose BC can positively interact with hydrophilic or hydrophobic biopolymers while being used in the biomedical domain. From the last two decades, the reinforcement of biopolymer-based biocomposites and its applicability with BC have increased in the research field. The harmony of hydrophobic biopolymers can be reduced due to the high moisture content of BC in comparison to hydrophilic biopolymers. Mechanical properties are the important parameters not only in producing green composite but also in dealing with tissue engineering, medical implants, and biofilm. The wide requisition of BC in medical as well as industrial fields has warranted the scaling up of the production of BC with added economy. This review provides a detailed overview of the production and properties of BC and several parameters affecting the production of BC and its biocomposites, elucidating their antimicrobial and antibiofilm efficacy with an insight to highlight their therapeutic potential.

Coproduction of bacterial cellulose and pear vinegar by fermentation of pear peel and pomace

Bacterial cellulose (BC)-derived materials are given significant attention due to their porous fibrous texture, high crystallinity and extraordinary physico-mechanical properties. The main reason for the restricted use of BC is its high production cost. To reduce the production cost, the suitability of pear residue for the production of BC and pear vinegar was investigated. Komagataeibacter rhaeticus and Komagataeibacter intermedius with high fermentation ability screened from the surface of vinegar film of millet fermentation were used to produce BC and pear vinegar simultaneously. Through response surface optimization, the maximum yield of BC from pear residue medium was 10.94 ± 0.42 g/L, which was higher than the synthesis medium generally used for Acetobacter strains. When pear residue medium was incubated at 30 °C for 7 days, the contents of total acid and soluble solids were greater than 0.3 g/100 mL and 3%, respectively, which met the standard requirements for fruit vinegar. The flavour components of pear vinegar were determined using gas chromatography-mass spectrometry. The pear vinegar showed similar flavour characteristics to conventional fruit vinegar. This research not only solved the utilization of agricultural resources but also avoided the discharge of waste liquid when producing BC. In addition, a more environmentally friendly and less expensive way to produce BC and pear vinegar was achieved.

Industrial-Scale Production and Applications of Bacterial Cellulose

Bacterial cellulose (BC) is a natural biomaterial synthesized by bacteria. It possesses a unique structure of cellulose nanofiber-weaved three-dimensional reticulated network that endows it excellent mechanical properties, high water holding capability and outstanding suspension stability. It is also characterized with high purity, high degree of crystallinity, great biocompatibility and biodegradability. Due to these advantages, BC has gained great attentions in both academic and industrial areas. This critical review summarizes the up-to-date development of BC production and application from an industrial perspective. Firstly, a fundamental knowledge of BC's biosynthesis, structure and properties is described, and then recent developments in the industrial fermentation of BC are introduced. Subsequently, the latest commercial applications of BC in the areas of food, personal care, household chemicals, biomedicine, textile, composite resin are summarized. Finally, a brief discussion of future development of BC industry is presented at the end.

Bacterial cellulose in food industry: Current research and future prospects

Bacterial cellulose, a pure exocellular polysaccharide produced by microorganisms, has many excellent properties as compared with plant-derived cellulose, including high water holding capability, high surface area, rheological properties, biocompatibility. Due to its suspending, thickening, water holding, stabilizing, bulking and fluid properties, BC has been demonstrated as a promising low calorie bulking ingredient for the development of novel rich functional foods of different forms such as powder gelatinous or shred foams, which facilitate its application in food industry. In this review, the recent reports on the biosynthesis, structure and general application of bacterial cellulose in food industry have been summarized and discussed. The main application of bacterial cellulose in current food industry includes raw food materials, additive ingredients, packing materials, delivery system, enzyme and cell immobilizers. In addition, we also propose the potential challenges and explore the solution of expanding the application of BC in various fields.

Production of high crystallinity type-I cellulose from Komagataeibacter hansenii JR-02 isolated from Kombucha tea

In this study, a bacterial cellulose (BC) producing strain was isolated from Kombucha tea and identified as Komagataeibacter hansenii JR-02 by morphological, physiological, and biochemical characterization and 16S rRNA sequence. Then, the media components and culture conditions for BC production were optimized. Result showed that the highest BC yield was 3.14 ± 0.22 and 8.36 ± 0.19 g/L after fermentation for 7 days under shaking and static cultivation, respectively. Moreover, it was interesting that JR-02 could produce BC in nitrogen-free medium with the highest yield of 0.76 ± 0.06 g/L/7days, and the possible nitrogen fixation gene nifH was cloned from its genomic DNA. The BC produced by JR-02 was type-I cellulose with high crystallinity and thermodynamic stability, which was revealed from Fourier transform infrared spectroscopy, X-ray diffraction, and thermogravimetric analysis methods. The crystallinity of static and shaking cultured BC were 91.76% and 90.69%, respectively. The maximum rate of weight loss of static and shaking BC occurred at temperature of approximately 373.1 °C and 369.1 °C, respectively. Overall, these results indicated that K. hansenii JR-02 had great potential to produce high crystallinity type-I BC in manufacture.

Isolation and characterisation of locally isolated Gluconacetobacter xylinus BCZM sp. with nanocellulose producing potentials

Recently, attention has been given to nanocellulose produced by bacteria due to its unique properties and environmentally friendly nature when compared with plant cellulose. Bacterial nanocellulose (BNC) producing isolate was successfully isolated from rotten fruits via dilution and spread plates method. Based on the biochemical characterisation and molecular analysis of the 16S rDNA gene, the isolate was identified as Gluconacetobacter xylinus BCMZ sp. Nanocellulose productivity was confirmed by the formation of the white gelatinous layer between air/liquid surfaces when the culture was cultivated under a stationary condition at 30°C. Successful purification of nanocellulose was achieved using alkaline treatment method. The Fourier transformed infrared spectrum showed a characteristics band signature of pure nanocellulose, by displaying strong absorption peaks at 3335.36 and 2901.40 cm−1 representing carbonyl and carbon–hydrogen bonding, respectively. Morphological characteristics of the BNC were determined by scanning electron microscopy (SEM). Elemental analysis of BNC was determined by energy dispersive X‐ray (SEM/EDX) analysis. The isolates BCZM showed significant nanocellulose production ability with a high degree of purity when compared with plant nanocellulose. BNC purification using 1 M NaOH solution is effective and eco‐friendly with no indication of recalcitrant formation as commonly found in plant nanocellulose purification steps.

An isolated cellulolytic Escherichia coli from bovine rumen produces ethanol and hydrogen from corn straw

BACKGROUND

Lignocellulosic biomass is the most abundant resource on earth. Lignocellulose is mainly composed of cellulose, hemicelluloses, and lignin. The special construction of three kinds of constituents led to the prevention of effective degradation. The goal of this work was to investigate the great potentials of bovine rumen for novel cellulolytic bacterial isolation, which may be used for chemicals and biofuel production from lignocellulose.

RESULTS

A cellulolytic strain, ZH-4, was isolated from Inner Mongolia bovine rumen. This strain was identified as Escherichia coli by morphological, physiological, and biochemical characteristics and 16S rDNA gene sequencing. The extracellular enzyme activity analysis showed that this strain produces extracellular cellulases with an exoglucanase activity of 9.13 IU, an endoglucanase activity of 5.31 IU, and a β-glucosidase activity of 7.27 IU at the pH 6.8. This strain was found to produce 0.36 g/L ethanol and 4.71 mL/g hydrogen from corn straw with cellulose degradation ratio of 14.30% and hemicellulose degradation ratio of 11.39%.

CONCLUSIONS

It is the first time that a cellulolytic E. coli was isolated and characterized form the bovine rumen. This provided a great opportunity for researchers to investigate the evolution mechanisms of the microorganisms in the rumen and provided great chance to produce biofuels and chemicals directly from engineered E. coli using consolidated bioprocess.

Fruit peels support higher yield and superior quality bacterial cellulose production

Fruit peels, also known as rinds or skins, are wastes readily available in large quantities. Here, we have used pineapple (PA) and watermelon (WM) peels as substrates in the culture media (containing 5 % sucrose and 0.7 % ammonium sulfate) for production of bacterial cellulose (BC). The bacterial culture used in the study, Komagataeibacter hansenii produced BC under static conditions as a pellicle at the air-liquid interface in standard Hestrin and Schramm (HS) medium. The yield obtained was ~3.0 g/100 ml (on a wet weight basis). The cellulosic nature of the pellicle was confirmed by CO2, H2O, N2, and SO2 (CHNS) analysis and Fourier transform infrared (FT-IR) spectroscopy. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) of the pellicle revealed the presence of flat twisted ribbonlike fibrils (70-130 nm wide). X-ray diffraction analysis proved its crystalline nature (matching cellulose I) with a crystallinity index of 67 %. When K. hansenii was grown in PA and WM media, BC yields were threefolds or fourfolds higher than those obtained in HS medium. Interestingly, textural characterization tests (viz., SEM, crystallinity index, resilience, hardness, adhesiveness, cohesiveness, springiness, shear energy and stress, and energy required for puncturing the pellicle) proved that the quality of BC produced in PA and WM media was superior to the BC produced in HS medium. These findings demonstrate the utility of the newly designed media for getting higher yields and better quality of BC, which could make fermentative production of BC more attractive on a commercial scale.

Applications of bacterial cellulose and its composites in biomedicine

Bacterial cellulose produced by few but specific microbial genera is an extremely pure natural exopolysaccharide. Besides providing adhesive properties and a competitive advantage to the cellulose over-producer, bacterial cellulose confers UV protection, ensures maintenance of an aerobic environment, retains moisture, protects against heavy metal stress, etc. This unique nanostructured matrix is being widely explored for various medical and nonmedical applications. It can be produced in various shapes and forms because of which it finds varied uses in biomedicine. The attributes of bacterial cellulose such as biocompatibility, haemocompatibility, mechanical strength, microporosity and biodegradability with its unique surface chemistry make it ideally suited for a plethora of biomedical applications. This review highlights these qualities of bacterial cellulose in detail with emphasis on reports that prove its utility in biomedicine. It also gives an in-depth account of various biomedical applications ranging from implants and scaffolds for tissue engineering, carriers for drug delivery, wound-dressing materials, etc. that are reported until date. Besides, perspectives on limitations of commercialisation of bacterial cellulose have been presented. This review is also an update on the variety of low-cost substrates used for production of bacterial cellulose and its nonmedical applications and includes patents and commercial products based on bacterial cellulose.

Structural studies of an exopolysaccharide produced by Gluconacetobacter diazotrophicus Pal5

Gluconacetobacter diazotrophicus is a nitrogen-fixing bacterium that has been found colonizing several plants. This acid-tolerant bacterium produces phytohormones that promote plant growth and is also able to grow in high-sugar concentrations. It has been demonstrated that exopolysaccharides (EPS), which are produced by strain Pal5 of G. diazotrophicus, play an important role in plant infection. We have investigated the structure of the EPS, which was produced by a strain of Pal5 grown in liquid medium containing mannitol as the sole carbon source. The results reveal an EPS with Glc, Gal, Man in a molar ratio of 6:3:1, respectively. NMR spectroscopy and chemical derivatization have revealed that the EPS structure has 4-O-substituted units of β-glucose, 3-O-substituted units of β-galactose and 2-O-substituted units of α-mannose. Glucose and galactose units linked at C6 were also found. The structure proposed herein is different from EPS produced by other species of Gluconacetobacter published to date.