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1.
Food Microbiol ; 99: 103828, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34119113

RESUMO

In this study, a composite film was prepared with bacterial cellulose (BC) of Gluconacetobacter xylinus and cell-free supernatant (CFS) of Enterococcus faecium TJUQ1, which was named BC-E. The optimum conditions for the preparation of the composite film with a minimal antibacterial activity were the soak of BC in 80 AU/mL CFS for 6 h. By scanning electron microscope observation, the surface network structure of BC-E was denser than that of BC. The tensile strength of BC and BC-E was 4.65 ± 0.88 MPa and 16.30 ± 0.92 MPa, the elongation at break of BC and BC-E was 3.33 ± 0.89% and 31.60 ± 1.15%, respectively, indicating the mechanical properties of BC-E were significantly higher than that of BC (P < 0.05). The swelling ratio of BC-E (456.67 ± 7.20%) was lower than that of BC (1377.78 ± 9.07%), demonstrating BC-E films presented better water resistance. BC-E films were soaked with 320 AU/mL CFS, and then used to pack the ground meat with 6.55 log10 CFU/g of Listeria monocytogenes. After 8 days of storage, the number of bacteria decreased by 3.16 log10 CFU/g. Similarly, total mesophilic bacterial levels in the ground meat decreased by 2.41 log10 CFU/g compared to control groups.


Assuntos
Antibacterianos/química , Celulose/química , Enterococcus faecium/metabolismo , Embalagem de Alimentos/instrumentação , Gluconacetobacter xylinus/metabolismo , Polímeros/química , Animais , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Hidrocarbonetos Aromáticos com Pontes/química , Hidrocarbonetos Aromáticos com Pontes/farmacologia , Celulose/metabolismo , Enterococcus faecium/química , Gluconacetobacter xylinus/química , Listeria monocytogenes/efeitos dos fármacos , Listeria monocytogenes/crescimento & desenvolvimento , Carne/análise , Carne/microbiologia , Polímeros/farmacologia , Suínos , Resistência à Tração
2.
Int J Biol Macromol ; 183: 2326-2336, 2021 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-34089760

RESUMO

In this study, a water-soluble bacterial cellulose sulfate (BCS) was prepared with sulfur trioxide pyridine complex (SO3· Py) in a lithium chloride (LiCl)/dimethylacetamide (DMAc) homogeneous solution system using bacterial cellulose (BC). The structural study showed that the value for the degrees of substitution of BCS was 1.23. After modification, the C-6 hydroxyl group of BC was completely substituted and the C-2 and C-3 hydroxyl groups were partially substituted. In an aqueous solution, the BCS existed as a linear polymer with irregular coil conformation, which was consistent with the findings observed using atomic force microscopy. The steady-state shear flow and dynamic viscoelasticity were systematically determined over a range of BCS concentrations (1 %-4 %, w/v) and temperature (5 °C-50 °C). Steady-state flow experiments revealed that BCS exhibited shear thinning behavior, which increased with an increase in concentration and a decrease in temperature. These observations were quantitatively demonstrated using the cross model. Moreover, based on the dynamical viscoelastic properties, we confirmed that BCS was a temperature-sensitive and weak elastic gel, which was somewhere between a dilute solution and an elastic gel. Therefore, considering the special synthetic strategy and rheological behavior, BCS might be used as a renewable material in the field of biological tissue engineering, especially in the manufacture of injectable hydrogels, cell scaffolds, and as a drug carrier.


Assuntos
Celulose/análogos & derivados , Gluconacetobacter xylinus/metabolismo , Configuração de Carboidratos , Celulose/química , Celulose/isolamento & purificação , Portadores de Fármacos , Elasticidade , Géis , Reologia , Temperatura , Tecidos Suporte , Viscosidade
3.
Carbohydr Polym ; 257: 117658, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33541667

RESUMO

Eco-friendly conductive polymer nanocomposites have garnered attention as an effective alternative for conventional conductive nanocomposites. Here, we report the fabrication and optimization of flexible, self-standing, and conductive bacterial cellulose/poly(3,4-ethylene dioxythiophene) (BC/PEDOT) nanocomposites using the vapor phase polymerization (VPP) method. Eco-friendly bacterial cellulose (BC) is used as a flexible matrix, and the highly conductive PEDOT polymer is introduced into the BC matrix to achieve electronic conductivity. We demonstrate that vapor phase polymerized BC/PEDOT composites exhibit more than 10 times lower sheet resistance (18 Ω/square) compared to solution polymerized BC/PEDOT (188 Ω/square). The resultant BC/PEDOT fabricated could be bent up to 100 times and completely rolled up without a notable decrease in electronic performance. Moreover, bent BC/PEDOT films enable operation of a green light-emitting diode (LED) light, indicating the flexibility and stability of conductive BC/PEDOT films. Overall, this study suggests a strategy for the development of eco-friendly, flexible, and conductive nanocomposite films.


Assuntos
Compostos Bicíclicos Heterocíclicos com Pontes/química , Celulose/química , Nanopartículas/química , Polímeros/química , Biomassa , Celulose/metabolismo , Condutividade Elétrica , Eletrodos , Gluconacetobacter xylinus/metabolismo , Luz , Microscopia Eletrônica de Varredura , Nanocompostos/química , Polimerização , Poliestirenos
4.
Int J Biol Macromol ; 175: 526-534, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33524483

RESUMO

Toxic compounds in pineapple peel waste hydrolysate (PPWH), namely formic acid, 5-hydroxymethylfurfural (HMF), and furfural, are the major predicament in its utilization as a carbon source for bacterial cellulose (BC) fermentation. A rapid detoxification procedures using atmospheric cold plasma (ACP) technique were employed to reduce the toxic compounds. ACP treatment allows the breakdown of toxic compounds without causing excessive breakdown of sugars. Herein, the performance of two available laboratory ACP reactors for PPWH detoxification was being demonstrated. ACP-reactor-1 (R1) runs on plasma power of 80-200 W with argon (Ar) plasma source, while ACP-reactor-2 (R2) runs at 500-600 W with air plasma source. Treatment in R1, at 200 W for 15 min, results in 74.06%, 51.38%, and 21.81% reduction of furfural, HMF, and formic acid. Treatment in R2 at 600 W gives 45.05%, 32.59%, and 60.41% reductions of furfural, HMF, and formic acid. The BC yield from the fermentation of Komagateibacter xylinus in the R1-treated PPWH, R2-treated PPWH, and untreated-PPWH is 2.82, 3.82, and 2.97 g/L, respectively. The results show that ACP treatment provides a novel detoxified strategy in achieving agricultural waste hydrolysate reuse in fermentation. Furthermore, the results also imply that untreated PPWH can be an inexpensive and sustainable resource for fermentation media supplementation.


Assuntos
Ananas/química , Celulose/síntese química , Gases em Plasma/química , Ananas/metabolismo , Bactérias/metabolismo , Celulose/metabolismo , Fermentação , Formiatos/química , Furaldeído/análogos & derivados , Furaldeído/química , Gluconacetobacter xylinus/metabolismo , Hidrólise , Hidrolisados de Proteína/química , Resíduos
5.
J Bacteriol ; 203(3)2021 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-33199282

RESUMO

Cellulose is a widespread component of bacterial biofilms, where its properties of exceptional water retention, high tensile strength, and stiffness prevent dehydration and mechanical disruption of the biofilm. Bacteria in the genus Gluconacetobacter secrete crystalline cellulose, with a structure very similar to that found in plant cell walls. How this higher-order structure is produced is poorly understood. We used cryo-electron tomography and focused-ion-beam milling of native bacterial biofilms to image cellulose-synthesizing Gluconacetobacter hansenii and Gluconacetobacter xylinus bacteria in a frozen-hydrated, near-native state. We confirm previous results suggesting that cellulose crystallization occurs serially following its secretion along one side of the cell, leading to a cellulose ribbon that can reach several micrometers in length and combine with ribbons from other cells to form a robust biofilm matrix. We were able to take direct measurements in a near-native state of the cellulose sheets. Our results also reveal a novel cytoskeletal structure, which we have named the cortical belt, adjacent to the inner membrane and underlying the sites where cellulose is seen emerging from the cell. We found that this structure is not present in other cellulose-synthesizing bacterial species, Agrobacterium tumefaciens and Escherichia coli 1094, which do not produce organized cellulose ribbons. We therefore propose that the cortical belt holds the cellulose synthase complexes in a line to form higher-order cellulose structures, such as sheets and ribbons.IMPORTANCE This work's relevance for the microbiology community is twofold. It delivers for the first time high-resolution near-native snapshots of Gluconacetobacter spp. (previously Komagataeibacter spp.) in the process of cellulose ribbon synthesis, in their native biofilm environment. It puts forward a noncharacterized cytoskeleton element associated with the side of the cell where the cellulose synthesis occurs. This represents a step forward in the understanding of the cell-guided process of crystalline cellulose synthesis, studied specifically in the Gluconacetobacter genus and still not fully understood. Additionally, our successful attempt to use cryo-focused-ion-beam milling through biofilms to image the cells in their native environment will drive the community to use this tool for the morphological characterization of other studied biofilms.


Assuntos
Celulose/ultraestrutura , Citoesqueleto/ultraestrutura , Gluconacetobacter/metabolismo , Gluconacetobacter/ultraestrutura , Acetobacteraceae/metabolismo , Acetobacteraceae/ultraestrutura , Biofilmes , Celulose/metabolismo , Cristalização , Citoesqueleto/metabolismo , Tomografia com Microscopia Eletrônica , Elétrons , Escherichia coli/metabolismo , Gluconacetobacter xylinus/metabolismo , Gluconacetobacter xylinus/ultraestrutura , Microfibrilas
6.
Carbohydr Polym ; 254: 117313, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33357876

RESUMO

Biotech nanocellulose (bacterial nanocellulose, BNC) is a high potential natural polymer. Moreover, it is the only cellulose type that can be produced biotechnologically using microorganisms resulting in hydrogels with high purity, high mechanical strength and an interconnecting micropore system. Recently, the subject of intensive research is to influence this biosynthesis to create function-determining properties. This review reports on the progress in product design and today's state of technical and medical applications. A novel, dynamic, template-based technology, called Mobile Matrix Reservoir Technology (MMR Tech), is highlighted. Thereby, shape, dimensions, surface properties, and nanonetwork structures can be designed in a process-controlled manner. The formed multilayer materials open up new applications in medicine and technology. Especially medical materials for cardiovascular and visceral surgery, and drug delivery systems are developed. The effective production of layer-structured composites and coatings are important for potential applications in the electronics, paper, food and packaging technologies.


Assuntos
Técnicas Biossensoriais/métodos , Biotecnologia/métodos , Celulose/química , Sistemas de Liberação de Medicamentos/métodos , Embalagem de Alimentos/métodos , Nanocompostos/química , Próteses e Implantes , Engenharia Tecidual/métodos , Acetobacteraceae/metabolismo , Gluconacetobacter xylinus/metabolismo , Hidrogéis/química
7.
Carbohydr Polym ; 252: 117137, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33183596

RESUMO

Bacterial cellulose (BC) and polyhydroxybutyrate (PHB) are microbial polymers considered to be promising biodegradable alternatives to fossil fuel derivatives. BC and PHB can be combined into a composite with enhanced mechanical properties. The synthesis processes of BC/PHB composites described until now are complicated with multiple steps. Here, BC/PHB composites were synthesized by a facile Gluconacetobacter xylinus and Ralstonia eutropha co-culture method generating BC and PHB simultaneously in situ. This co-culture approach ensured a certain level of control over the synthesis process. By simply varying the R. eutropha inoculum, the weight ratio of PHB into BC/PHB was adjusted from 15.62 to 42.88 %. The fabricated composites were networks of BC fibers connecting PHB particles. BC/PHBs were characterized by thermal and mechanical analyses and exhibited a 2.6 times higher capacity for toxic copper adsorption than pure BC. The co-culture technique described here is a simple synthesis method to obtain BC/PHB with adjustable characteristics.


Assuntos
Celulose/biossíntese , Cupriavidus necator/metabolismo , Gluconacetobacter xylinus/metabolismo , Hidroxibutiratos/metabolismo , Poliésteres/metabolismo , Biocombustíveis , Técnicas de Cocultura , Microbiologia Industrial
8.
Carbohydr Polym ; 253: 117247, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33279002

RESUMO

In this work, we present a novel ex situ modification of bacterial cellulose (BC) polymer, that significantly improves its ability to absorb water after drying. The method involves a single inexpensive and easy-to-perform process of BC crosslinking, using citric acid along with catalysts, such as disodium phosphate, sodium bicarbonate, ammonium bicarbonate or their mixtures. In particular, the mixture of disodium phosphate and sodium bicarbonate was the most promising, yielding significantly greater water capacity (over 5 times higher as compared to the unmodified BC) and slower water release (over 6 times as compared to the unmodified BC). Further, our optimized crosslinked BC had over 1.5x higher water capacity than modern commercial dressings dedicated to highly exuding wounds, while exhibiting no cytotoxic effects against fibroblast cell line L929 in vitro. Therefore, our novel BC biomaterial may find application in super-absorbent dressings, designed for chronic wounds with imbalanced moisture level.


Assuntos
Absorção Fisico-Química , Bandagens , Materiais Biocompatíveis/química , Celulose/química , Reagentes para Ligações Cruzadas/química , Gluconacetobacter xylinus/metabolismo , Polissacarídeos Bacterianos/química , Cicatrização , Animais , Materiais Biocompatíveis/farmacologia , Catálise , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Celulose/farmacologia , Ácido Cítrico/química , Reagentes para Ligações Cruzadas/farmacologia , Fibroblastos/efeitos dos fármacos , Camundongos , Fosfatos/química , Polissacarídeos Bacterianos/farmacologia , Bicarbonato de Sódio/química , Água/química
9.
Carbohydr Polym ; 253: 117220, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33278983

RESUMO

Bacterial cellulose (BC) is a substrate material with high purity and robust mechanical strength, but due to its small pore size and relatively expensive price, it is restricted as an oil-/water separation membrane. In this study, cheaper plant cellulose needle-leaf bleached kraft pulp (NBKP) was added to BC to increase the pore size of the composite membrane, and a superhydrophobic/superoleophilic membrane was prepared for oil-/water separation. The modified membrane surface displayed a petal-like micro-structure and a water contact angle (WCA) of 162.3°, while the oil contact angle was decreased to 0°. What's more, the membrane exhibited excellent oil-/water separation under gravity, recyclability, and a separation efficiency (>95 %), and it was both pH and salt resistant. The membrane also remained durably hydrophobic after 10 separation cycles. And the separation methodology is expected to be highly energy-efficient.


Assuntos
Celulose/química , Gluconacetobacter xylinus/metabolismo , Gravitação , Química Verde/métodos , Interações Hidrofóbicas e Hidrofílicas , Membranas Artificiais , Óleos/química , Polissacarídeos Bacterianos/química , Água/química , Concentração de Íons de Hidrogênio , Lignina/química , Folhas de Planta/química , Polissacarídeos/química , Porosidade , Resistência à Tração
10.
ACS Appl Mater Interfaces ; 12(47): 52467-52478, 2020 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-33170636

RESUMO

Despite the widely explored biomaterial scaffolds in vascular tissue engineering applications lately, no ideal platform has been provided for small diameter synthetic vascular grafts mainly due to the thrombosis issue. Endothelium is the only known completely non-thrombogenic material; so, functional endothelialization onto vascular biomaterials is critical in maintaining the patency of vascular networks. Bacterial cellulose (BC) is a natural biomaterial with superior biocompatibility and appropriate hydrophilicity as potential vascular grafts. In previous studies, surface modification of active peptides such as Arg-Gly-Asp (RGD) sequences onto biomaterials has been proven to achieve accelerated and selective endothelial cell (EC) adhesion. In our study, we demonstrated a new strategy to remotely regulate the adhesion of endothelial cells based on an oscillating magnetic field and achieve successful endothelialization on the modified BC membranes. In details, we synthesized bacterial cellulose (BC), magnetic BC (MBC), and RGD peptide-grafted magnetic BC (RMBC), modified with the HOOC-PEG-COOH-coated iron oxide nanoparticles (PEG-IONs). The endothelial cells were cultured on the three materials under different frequencies of an oscillating magnetic field, including "stationary" (0 Hz), "slow" (0.1 Hz), and "fast" (2 Hz) groups. Compared to BC and MBC membranes, the cells on RMBC membranes generally show better adhesion and proliferation. Meanwhile, the "slow" frequency of a magnetic field promotes this phenomenon on RMBC and achieves endothelialization after culture for 4 days, whereas "fast" inhibits the cellular attachment. Overall, we demonstrate a non-invasive and convenient method to regulate the endothelialization process, with promising applications in vascular tissue engineering.


Assuntos
Materiais Biocompatíveis/química , Celulose/química , Nanopartículas Metálicas/química , Animais , Materiais Biocompatíveis/farmacologia , Adesão Celular/efeitos dos fármacos , Linhagem Celular , Células Endoteliais/citologia , Células Endoteliais/metabolismo , Compostos Férricos/química , Gluconacetobacter xylinus/metabolismo , Campos Magnéticos , Camundongos , Oligopeptídeos/química , Polietilenoglicóis/química
11.
Cardiovasc Eng Technol ; 11(6): 646-654, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33205361

RESUMO

PURPOSE: The paper present findings from an in vitro experimental study of a stentless human aortic bioprosthesis (HAB) made of bacterial cellulose (BC). Three variants of the basic model were designed and tested to identify the valve prosthesis with the best performance parameters. The modified models were made of BC, and the basic model of pericardium. METHODS: Each model (named V1, V2 and V3) was implanted into a 90 mm porcine aorta. Effective Orifice Area (EOA), rapid valve opening time (RVOT) and rapid valve closing time (RVCT) were determined. The flow resistance of each bioprosthesis model during the simulated heart systole, i.e. for the mean differential pressure (ΔP) at the time of full valve opening was measured. All experimental specimens were exposed to a mean blood pressure (MBP) of 90.5 ± 2.3 mmHg. RESULTS: The V3 model demonstrated the best performance. The index defining the maximum opening of the bioprosthesis during systole for models V1, V2 and V3 was 2.67 ± 0.59, 2.04 ± 0.23 and 2.85 ± 0.59 cm2, respectively. The mean flow rate through the V3 valve was 5.7 ± 1, 6.9 ± 0.7 and 8.9 ± 1.4 l/min for stroke volume (SV) of 65, 90 and 110 mL, respectively. The phase of immediate opening and closure for models V1, V2 and V3 was 8, 7 and 5% of the cycle duration, respectively. The mean flow resistance of the models was: 4.07 ± 2.1, 4.28 ± 2.51 and 5.6 ± 2.32 mmHg. CONCLUSIONS: The V3 model of the aortic valve prosthesis is the most effective. In vivo tests using BC as a structural material for this model are recommended. The response time of the V3 model to changed work conditions is comparable to that of a healthy human heart. The model functions as an aortic valve prosthesis in in vitro conditions.


Assuntos
Aorta/cirurgia , Bioprótese , Celulose/isolamento & purificação , Gluconacetobacter xylinus/metabolismo , Implante de Prótese de Valva Cardíaca/instrumentação , Próteses Valvulares Cardíacas , Animais , Aorta/fisiopatologia , Hemodinâmica , Teste de Materiais , Desenho de Prótese , Sus scrofa
12.
J Microbiol Biotechnol ; 30(9): 1430-1435, 2020 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-32627756

RESUMO

Bacterial cellulose (BC) has outstanding physical and chemical properties, including high crystallinity, moisture retention, and tensile strength. Currently, the major producer of BC is Komagataeibacter xylinus. However, due to limited tools of expression, this host is difficult to engineer metabolically to improve BC productivity. In this study, a regulated expression system for K. xylinus with synthetic ribosome binding site (RBS) was developed and used to engineer a BC biosynthesis pathway. A synthetic RBS library was constructed using green fluorescent protein (GFP) as a reporter, and three synthetic RBSs (R4, R15, and R6) with different strengths were successfully isolated by fluorescence-activated cell sorting (FACS). Using synthetic RBS, we optimized the expression of three homologous genes responsible for BC production, pgm, galU, and ndp, and thereby greatly increased it under both static and shaking culture conditions. The final titer of BC under static and shaking conditions was 5.28 and 3.67 g/l, respectively. Our findings demonstrate that reinforced metabolic flux towards BC through quantitative gene expression represents a practical strategy for the improvement of BC productivity.


Assuntos
Vias Biossintéticas/genética , Celulose/metabolismo , Gluconacetobacter xylinus/metabolismo , Ribossomos/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Sequência de Bases , Sítios de Ligação/genética , Celulose/genética , Biblioteca Gênica , Gluconacetobacter xylinus/genética , Engenharia Metabólica , Análise do Fluxo Metabólico
13.
Carbohydr Polym ; 234: 115835, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32070499

RESUMO

Antibacterial dressing can prevent the occurrence of many infections of wounds. Bacterial cellulose (BC) has the ability to carry and transfer the medicine to achieve a wound healing bandage. In this study, Carbon Quantum Dots-Titanium dioxide (CQD-TiO2) nanoparticles (NP) were added to BC as antibacterial agents. FTIR Spectroscopy illuminated that NPs were well-bonded to BC. Interestingly, MIC test proved that BC/CQD-TiO2 nanostructure (NS) has anti-bacterial properties against Staphylococcus aureus. The findings indicated that, CQD-TiO2 NPs have stronger antibacterial properties with better tensile strength compared to CQD NPs, in a concentration-dependent manner. Toxicity of CQD-TiO2 NPs on human L929 fibroblast cells was also evaluated. Most importantly, the results of the scratch test indicated that the NS was effective in wound healing in L929 cells. The approach in this study may provide an alternative to make an antibacterial wound dressing to achieve an effective drug-based bandage.


Assuntos
Antibacterianos/farmacologia , Carbono/farmacologia , Celulose/farmacologia , Gluconacetobacter xylinus/química , Nanocompostos/química , Pontos Quânticos/química , Titânio/farmacologia , Antibacterianos/biossíntese , Antibacterianos/química , Carbono/química , Carbono/metabolismo , Celulose/biossíntese , Celulose/química , Gluconacetobacter xylinus/metabolismo , Humanos , Testes de Sensibilidade Microbiana , Tamanho da Partícula , Pontos Quânticos/metabolismo , Staphylococcus aureus/efeitos dos fármacos , Propriedades de Superfície , Titânio/química , Titânio/metabolismo
14.
J Agric Food Chem ; 68(9): 2696-2701, 2020 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-32031789

RESUMO

All-cellulose composites are usually prepared by removing impurities and using a surface-selective dissolution approach, which detract significantly from their environment-friendly properties. In this paper, we report an environment-friendly approach to fabricate all-cellulose nanofiber composites from stack-up bacterial cellulose (BC) hydrogels via self-aggregation forces of the hydrogen bond by water-based processing. Structural and mechanical properties of BC-laminated composites have been investigated. The results indicated that BC composites possess the structure of all nanofibers, a tensile strength of 116 MPa, and a storage modulus of 25 GPa. Additionally, the interfacial shear strength and tensile strength of piece-hot-press BC demonstrate the strong self-aggregation forces of BC nanofibers. Thus, BC-laminated composites will be attractive in structural material.


Assuntos
Celulose/química , Gluconacetobacter xylinus/química , Hidrogéis/química , Nanofibras/química , Celulose/metabolismo , Gluconacetobacter xylinus/crescimento & desenvolvimento , Gluconacetobacter xylinus/metabolismo , Hidrogéis/metabolismo , Fenômenos Mecânicos , Resistência à Tração
15.
Lab Chip ; 20(3): 626-633, 2020 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-31919490

RESUMO

Bacterial cellulose (BC), a renewable type of cellulose, has been used in the manufacture of foods, cosmetics, and biomedical products. To produce BC, a high-throughput single-bacterium measurement is necessary to identify the functional bacteria that can produce BC with sufficient amount and desirable morphology. In this study, a continuous-flow intelligent optofluidic device was developed to enable high-throughput single-bacterium profiling of BC. Single bacteria were incubated in agarose hydrogel particles to produce BC with varied densities and structures. An intelligent convolutional neural network (CNN) computational method was developed to analyze the scattering patterns of BC. The BC production and morphology were determined with a throughput of ∼35 bacteria per second. A total of ∼105 single-bacterium BC samples were characterized within 3 hours. The high flexibility of this approach facilitates high-throughput comprehensive single-cell production analysis for a range of applications in engineering biology.


Assuntos
Acetobacteraceae/química , Materiais Biocompatíveis/metabolismo , Celulose/biossíntese , Gluconacetobacter xylinus/química , Dispositivos Lab-On-A-Chip , Acetobacteraceae/metabolismo , Materiais Biocompatíveis/química , Celulose/química , Gluconacetobacter xylinus/metabolismo , Fenômenos Ópticos
16.
Carbohydr Polym ; 232: 115788, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31952596

RESUMO

Bacterial cellulose (BC) has received considerable attention as an environment-friendly, biodegradable nanomaterial. In this study, the strain Komagataeibacter sp. nov. CGMCC 17276, which showed rapid cell growth and high BC-production ability, was isolated and classified into a novel species in the Komagataeibacter genus. Four BC synthase operons were annotated using whole-genome analysis, partially explaining the high BC yield of strain CGMCC 17276. Operons bcs Ⅱ and bcs Ⅲ showed high transcriptional levels under static and agitated culture conditions, indicating their importance in BC synthesis. Of the eight suitable carbon sources identified by whole-genome analysis, the highest BC production was achieved using glycerol as a single carbon source. Finally, waste glycerol was successfully used as an eco-friendly and sustainable strategy for BC production. This study provides valuable insights into the mechanism of BC synthesis, genetic structure of BC-producing strains, and industrialization of BC production using an eco-friendly and low-cost strategy.


Assuntos
Celulose/biossíntese , Gluconacetobacter xylinus/genética , Celulose/genética , DNA Bacteriano/genética , Fermentação , Gluconacetobacter xylinus/metabolismo , Análise de Sequência de DNA
17.
Prep Biochem Biotechnol ; 50(4): 330-340, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31747333

RESUMO

Apple pomace was explored as alternative feedstock for producing bacterial cellulose (BC) by Gluconacetobacter xylinus following a cellulase saccharification performed after pretreatment of 1-allyl-3-methylimidazolium chloride ([AMIM]Cl). The dissolving process of apple pomace cellulose was observed by polarized light microscopy (PLM). As FT-IR and XRD results demonstrated, the IL pretreatment proved to be a physical process and no changes in the crystalline structure occurred during the pretreatment. However, the SEM result showed that more fissures and breakages appeared on the surface of pomace microfibers after IL-pretreating, which increased the contact area with cellulase and improved the enzymatic hydrolysis efficiency. An enhancing effect on the BC yield has been observed, 27% higher yield of BC obtained from hydrolysate as compared to sucrose-based medium indicates efficiency of IL-treated apple pomace to serve as high quality feedstock in BC production.


Assuntos
Celulose/biossíntese , Gluconacetobacter xylinus/metabolismo , Líquidos Iônicos/química , Celulase/química , Frutas/química , Frutas/metabolismo , Hidrólise , Malus/química , Malus/metabolismo
18.
Biomacromolecules ; 21(2): 508-516, 2020 02 10.
Artigo em Inglês | MEDLINE | ID: mdl-31756098

RESUMO

This work demonstrates a general strategy for introducing remarkable changes in matrix organization and, consequently, functional properties of bacterial cellulose (BC). BC-producing cells were induced, using a well-defined atomized droplet nutrient delivery (ADND) system, to form pellicles with a regular layered morphology that persists throughout the mat depth. In contrast, the morphology of mats formed by conventional static medium nutrient delivery (SMND) is irregular with no distinguishable pattern. ADND also resulted in larger meso-scale average pore sizes but did not alter the fibril diameter (∼70 nm) and crystallinity index (92-95%). The specific modulus and specific tensile strength of ADND mats are higher than those of SMND mats. This is due to the regularity of dense layers that are present in ADND mats that are able to sustain tensile loads, when applied parallel to these layers. The density of BC films prepared by ADND is 1.63-fold lower than that of the SMND BC film. Consequently, the water contents (g/g) of ADND- and SMND-prepared BC mats are 263 ± 8.85 and 99.6 ± 2.04, respectively. A model that rationalizes differences in mat morphology resulting from these nutrient delivery methods based on nutrient and oxygen concentration gradients is proposed. This work raises questions as to the extent that ADND can be used to fine-tune the matrix morphology and how the resulting lower density mats will alter the diffusion of actives from the films to wound sites and increase the ability of cells to infiltrate the matrix during tissue engineering.


Assuntos
Técnicas Bacteriológicas/métodos , Celulose/biossíntese , Celulose/química , Meios de Cultura/farmacologia , Gluconacetobacter xylinus/crescimento & desenvolvimento , Técnicas Bacteriológicas/instrumentação , Meios de Cultura/química , Módulo de Elasticidade , Desenho de Equipamento , Gluconacetobacter xylinus/metabolismo , Microscopia Eletrônica de Varredura , Resistência à Tração
19.
Appl Microbiol Biotechnol ; 103(21-22): 9143-9154, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31650194

RESUMO

In this work, recycled paper sludge (RPS), composed of non-recyclable fibres, was used as a carbon source for bacterial nanocellulose (BNC) production. The biomass was enzymatically hydrolysed with Cellic CTec 2 to produce a sugar syrup with 45.40 g/L glucose, 1.69 g/L cellobiose and 2.89 g/L xylose. This hydrolysate was used for the optimization of BNC fermentation by static culture, using Komagataeibacter xylinus ATCC 700178, through response surface methodology (RSM). After analysis and validation of the model, a maximum BNC yield (5.69 g/L, dry basis) was obtained using 1.50% m/v RPS hydrolysate, 1.0% v/v ethanol and 1.45% m/v yeast extract/peptone (YE/P). Further, the BNC obtained was used to produce composites. A mixture of an amino-PolyDiMethylSiloxane-based softener, polyethyleneglycol (PEG) 400 and acrylated epoxidized soybean oil (AESO), was incorporated into the BNC membranes through an exhaustion process. The results show that BNC composites with distinct performances can be easily designed by simply varying the polymers percentage contents. This strategy represents a simple approach towards the production of BNC and BNC-based composites.


Assuntos
Celulose/metabolismo , Gluconacetobacter xylinus/metabolismo , Esgotos/microbiologia , Purificação da Água/métodos , Fermentação , Microscopia Eletrônica de Varredura , Espectroscopia de Infravermelho com Transformada de Fourier
20.
Nat Commun ; 10(1): 4650, 2019 10 11.
Artigo em Inglês | MEDLINE | ID: mdl-31604956

RESUMO

Gluconacetobacter xylinus (G. xylinus) metabolism is activated by oxygen, which makes the formation of an air-medium interface critical. Here we report solid matrix-assisted 3D printing (SMAP) of an incubation medium surface and the 3D fabrication of bacterial cellulose (BC) hydrogels by in situ biosynthesis of G. xylinus. A printing matrix of polytetrafluoroethylene (PTFE) microparticles and a hydrogel ink containing an incubation medium, bacteria, and cellulose nanofibers (CNFs) are used in the SMAP process. The hydrogel ink can be printed in the solid matrix with control over the topology and dimensional stability. Furthermore, bioactive bacteria produce BC hydrogels at the surface of the medium due to the permeability of oxygen through the PTFE microparticle layer. The flexibility of the design is verified by fabricating complex 3D structures that were not reported previously. The resulting tubular BC structures suggest future biomedical applications, such as artificial blood vessels and engineered vascular tissue scaffolding. The fabrication of a versatile free-form structure of BC has been challenged due to restricted oxygen supplies at the medium and the dimensional instability of hydrogel printing. SMAP is a solution to the problem of fabricating free-form biopolymer structures, providing both printability and design diversity.


Assuntos
Gluconacetobacter xylinus/fisiologia , Engenharia Tecidual/métodos , Técnicas de Cultura de Células/instrumentação , Celulose , Meios de Cultura , Gluconacetobacter xylinus/crescimento & desenvolvimento , Gluconacetobacter xylinus/metabolismo , Hidrogéis/química , Nanofibras , Oxigênio , Impressão Tridimensional , Tecidos Suporte/química
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