Biosynthesis and Characterization of Bacterial Cellulose Produced by a Wild Strain of Acetobacter spp.

2013 ◽  
Vol 1498 ◽  
pp. 109-114
Author(s):  
Fatima Yassine ◽  
Michael Ibrahim ◽  
Maria Bassil ◽  
Ali Chokr ◽  
Anatoli Serghei ◽  
...  
Keyword(s):  
Bacterial Cellulose ◽  
Cellulose Nanofibers ◽  
Thermo Gravimetric Analysis ◽  
Wild Strain ◽  
Culture Conditions ◽  
Gravimetric Analysis ◽  
Wild Strains ◽  
Nanomaterials Synthesis ◽  
Static Conditions ◽  
Container Shape

ABSTRACTMany advances in nanomaterials synthesis have been recorded during the last 30 years. Bacterial cellulose (BC) produced by bacteria belonging to the genera Acetobacter, Rhizobium, Agrobacterium, and Sarcina is acquiring major importance as one of many eco-friendly materials with great potential in the biomedical field. The shape of BC bulk is sensitive to the container shape and incubation conditions such as agitation, carbon source, rate of oxygenation, electromagnetic radiation, temperature, and pH. The challenge is to control the dimension and the final shape of biosynthesized cellulose, by the optimization of culture conditions. The production of 3D structures based on BC is important for many industrial and biomedical applications such as paper and textile industries, biological implants, burn dressing material, and scaffolds for tissue regeneration. In our work, wild strains of Acetobacter spp. were isolated from homemade vinegar then purified and used for cellulose production. Four media of different initial viscosity were used. Cultures were performed under static conditions at 29°C, in darkness. The dimensions and texture of obtained bacterial cellulose nanofibers were studied using scanning electron microscopy (SEM). X-ray diffraction (XRD) showed that the biosynthesized material has a cellulose I crystalline phase characterized by three crystal planes. fourrier transform infrared spectroscopy (FTIR) data confirmed the chemical nature of the fibers. Thermo-gravimetric analysis (TGA) showed that BC preserves a relatively superior non-degradable fraction compared to microcrystalline cellulose.

Characterisation of Hydroxyapatite/Bacterial Cellulose Nanocomposites

2009 ◽  
Vol 17 (6) ◽  
pp. 353-358 ◽  
Author(s):  
Shengnan Zhang ◽  
Guangyao Xiong ◽  
Fang He ◽  
Yuan Huang ◽  
Yulin Wang ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Bacterial Cellulose ◽  
Photoelectron Spectroscopy ◽  
Thermo Gravimetric Analysis ◽  
Hydroxyl Groups ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Cellulose Nanocomposites

A novel nanocomposite material consisting of hydroxyapatite (HAp) deposited on a phosphorylated bacterial cellulose (BC) has been synthesised via a biomimetic route. X-ray photoelectron spectroscopy (XPS) showed that phosphate groups were successfully introduced to the hydroxyl groups of BC by phosphorylation reaction to promote the growth of calcium phosphate. Transmission electron microscopy (TEM) and the corresponding selected area electron diffraction (SAED) patterns of HAp/BC demonstrated that HAp crystals wrap the surfaces of BC fibres. In this work, HAp/BC nanocomposites were studied using thermo-gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The TGA result suggested that HAp/BC nanocomposite, similar to natural bone in terms of composition, contained carbonate ions, in agreement with our previous Fourier transform infrared (FTIR) spectroscopy results. Thermal behaviour differences between BC and HAp/BC were observed by differential scanning calorimetry (DSC). The thermal stability of HAp/BC obtained from DSC showed an improvement when compared to that of a pure BC sample.

The Effect of Bacterial Cellulose on the Mechanical and Thermal Expansion Properties of Kenaf/Polylactic Acid Composites

2011 ◽  
Vol 117-119 ◽  
pp. 1343-1351 ◽  
Author(s):  
Prakit Sukyai ◽  
Klana Rong Sriroth ◽  
Byoung Ho Lee ◽  
Joong Kim Hyun
Keyword(s):  
Thermal Stability ◽  
Bacterial Cellulose ◽  
Storage Modulus ◽  
Loss Modulus ◽  
Thermo Gravimetric Analysis ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Fiber Volume ◽  
Nano Cellulose ◽  
Electron Microscopes

The reinforcement of PLA matrix with natural fibers aims to generate the sustainable biocomposites. Kenaf fiber (KF) and bacterial cellulose (BC) were employed to reinforce and diminish the usage of PLA matrix. Particularly, BC is nano-cellulose which was anticipated to increased interfacial area and therefore low volume fractions of additives. That was consequently to attain mechanical property improvement. Thus, the incorporation of KF and BC reinforced PLA composites was investigated. The extrusion method was utilized and materials were mixed outside prior to adding. The specimens were examined mechanical testing, Dynamic Mechanical Analysis (DMA), Differential Scanning Calorimetry (DSC), Thermo Gravimetric Analysis (TGA) and Scanning Electron Microscopes (SEM). The mechanical study revealed that the increment of elastic modulus increased concomitantly with the augmentation of KF content. Interestingly, PLA/KF/BC sample at ratio of 60/39/1 wt.% was efficiently to maintain tensile and flexural strength comparing to 50% reduction of without BC sample with equal fiber volume. Therefore, it could recognize that mechanical properties was improved by using low amount of nano-cellulose. This would be a high aspect ratio of BC that capable to connect between PLA matrix and KF which enhanced a large contact surface and therefore excellent coherence. The temperature dependence of storage, loss and tan delta was determined by DMA. A decrease of storage modulus was consistent with increasing of temperature, result from softening of the composites. Loss modulus was increased approximately at Tg which related to storage modulus cause. In addition, the tan delta peaks of PLA and composites were around 60°C and it did not significantly shift when emerged of fiber. DSC of both composites indicated an influence of fiber on the crystallization and enthalpy. On the other hand, glass transition and melting temperature did not significantly affect. The composites exhibited a small reduction of thermal stability when examined by TGA analysis. Notwithstanding, BC showed an improvement of thermal stability of PLA/KF/BC sample at 40 wt.% total fiber content. The linkage of BC between PLA matrix and KF was monitored by SEM.

scholarly journals Production of bacterial cellulose using Gluconacetobacter kombuchae immobilized on Luffa aegyptiaca support

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sameeha Syed Abdul Rahman ◽  
T. Vaishnavi ◽  
G. Sai Vidyasri ◽  
K. Sathya ◽  
P. Priyanka ◽  
...  
Keyword(s):  
Nitrogen Source ◽  
Bacterial Cellulose ◽  
Large Scale ◽  
Positive Impact ◽  
Thermo Gravimetric Analysis ◽  
Maximum Yield ◽  
Inoculum Size ◽  
Gravimetric Analysis ◽  
Initial Ph ◽  
Luffa Aegyptiaca

AbstractThe present work report for the first time on the production of bacterial cellulose (BC) using natural loofa sponge (Luffa aegyptiaca) as a scaffold for the immobilization of Gluconacetobacter kombuchae. Bacterial cellulose (BC) are recently gained more attention in several fields including biological and biomedical applications due to their outstanding physico-chemical characteristics including high thermal stability, easy biodegradability, good water holding capacity, high tensile strength, and high degree of polymerization. The increase in requirement of alternative method for the enhancement of BC production under economical aspect develops a positive impact in large scale industries. In this study, Luffa aegyptiaca (LA) was introduced in a separate fermentation medium so as to enhance the concentration of BC production by Gluconacetobacter kombuchae. Different process/medium parameters such as initial pH, static/shaking condition, inoculum size, nitrogen source, C/N ratio, supplements (ethanol and acetic acid) were analysed for the production of bacterial cellulose using LA support. The maximum yield of BC was obtained using following condition: culturing condition -shaking; initial pH − 5.5; nitrogen source- yeast extract, C/N ratio – 40 and supplement—ethanol. The characterization of the BC was examined using Fourier Transform Infra-Red spectroscopy and thermo gravimetric analysis. The biofilm formation on the surface of LA was examined by SEM photographs. Thus, implementation of LA as a support in shaking fermentation under suitable medium/process variables enhanced the BC production.

scholarly journals Structure Optimization of Cellulose Nanofibers/Poly(Lactic Acid) Composites by the Sizing of AKD

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4119
Author(s):  
Lei Li ◽  
Minjian Cao ◽  
Jingdan Li ◽  
Cong Wang ◽  
Shengjuan Li
Keyword(s):  
Lactic Acid ◽  
Cellulose Nanofibers ◽  
Thermo Gravimetric Analysis ◽  
Poly Lactic Acid ◽  
Hydroxyl Groups ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Alkyl Ketene Dimer ◽  
Interfacial Compatibility ◽  
Ketone Ester

Recently, cellulose nanofibers (CNF) are used as one novel fillers to reinforce poly(lactic acid) (PLA) matrix and form PLA green nanocomposites. In the present work, alkyl ketene dimer (AKD) was used as the sizing of CNF to improve the interfacial compatibility between the hydrophilic CNF and the hydrophobic PLA. The interactions between the AKD and CNF were characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR), which showed the formation of ketone ester structure between AKD and the hydroxyl groups of CNF. Thermo gravimetric analysis (TGA) showed the little reduced thermal stability of the AKD-CNF/PLA composites. The AKD-CNF/PLA morphology has rough surfaces due to the incorporation of cellulose nanofibers. The mechanical properties of AKD-CNF/PLA were tested by tensile testing, which discovered more AKD-CNF content enhances stress–strain performance. The highest tensile strength of composites was obtained for PLA with 5.0 wt.% AKD-cellulose, which is almost nine times higher than that of the pure PLA.

Synthesis of Smart Mesoporous Materials

2003 ◽  
Vol 775 ◽  
Author(s):  
G.V.Rama Rao ◽  
Qiang Fu ◽  
Linnea K. Ista ◽  
Huifang Xu ◽  
S. Balamurugan ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Mesoporous Materials ◽  
Fluorescent Dyes ◽  
Thermo Gravimetric Analysis ◽  
Molecular Transport ◽  
Solute Diffusion ◽  
Gravimetric Analysis ◽  
Stimuli Responsive ◽  
Porous Network ◽  
Hybrid Mesoporous Materials

AbstractThis study details development of hybrid mesoporous materials in which molecular transport through mesopores can be precisely controlled and reversibly modulated. Mesoporous silica materials formed by surfactant templating were modified by surface initiated atom transfer radical polymerization of poly(N-isopropyl acrylamide) (PNIPAAm) a stimuli responsive polymer (SRP) within the porous network. Thermo gravimetric analysis and FTIR spectroscopy were used to confirm the presence of PNIPAAm on the silica surface. Nitrogen porosimetry, transmission electron microscopy and X-ray diffraction analyses confirmed that polymerization occurred uniformly within the porous network. Uptake and release of fluorescent dyes from the particles was monitored by spectrofluorimetry and scanning laser confocal microscopy. Results suggest that the presence of PNIPAAm, a SRP, in the porous network can be used to modulate the transport of aqueous solutes. At low temperature, (e.g., room temperature) the PNIPAAm is hydrated and extended and inhibits transport of analytes; at higher temperatures (e.g., 50°C) it is hydrophobic and is collapsed within the pore network, thus allowing solute diffusion into or out of the mesoporous silica. The transition form hydrophilic to hydrophobic state on polymer grafted mesoporous membranes was determined by contact angle measurements. This work has implications for the development of materials for the selective control of transport of molecular solutes in a variety of applications.

Coordination Compounds of Some 3d-Transition Metal Ions with N1-[4-(4-bromo-phenylsulfonyl)-benzoyl]-N4-(4-methoxyphenyl)- thiosemicarbazide

2008 ◽  
Vol 59 (7) ◽  
Author(s):  
Madalina Angelusiu ◽  
Maria Negoiu ◽  
Stefania-Felicia Barbuceanu ◽  
Tudor Rosu
Keyword(s):  
Coordination Compounds ◽  
Magnetic Moments ◽  
Thermo Gravimetric Analysis ◽  
Electronic Spectroscopy ◽  
Transition Metal Ions ◽  
Synthesis And Characterization ◽  
Gravimetric Analysis ◽  
Thermo Gravimetric ◽  
New Compounds

The paper presents the synthesis and characterization of Cu(II), Co(II), Ni(II), Cd(II), Zn(II) and Hg(II) complexes with N1-[4-(4-bromo-phenylsulfonyl)-benzoyl]-N4-(4-methoxyphenyl)-thiosemicarbazide. The new compounds were characterized by IR, EPR, electronic spectroscopy, magnetic moments, thermo-gravimetric analysis and elemental analysis.

Collagen And Carbon-Ferrous Nanoparticles Used As A Green Energy Composite Material For Energy Storage Devices

2020 ◽  
Vol 13 ◽  
Author(s):  
Inbasekaran S. ◽  
G. Thiyagarajan ◽  
Ramesh C. Panda ◽  
S. Sankar
Keyword(s):  
Composite Material ◽  
Thermo Gravimetric Analysis ◽  
Value Added ◽  
Green Energy ◽  
Nano Particles ◽  
Hydroxyl Group ◽  
Gravimetric Analysis ◽  
Circuit Testing ◽  
Battery Cell ◽  
Dc Voltage

Background:: Chrome shavings, a bioactive material, are generated from tannery as waste material. These chrome shaving can be used for the preparation of many value-added products. Objective:: One such attempt is made to use these chrome shaving wastes as a composite bio-battery to produce DC voltage, an alternate green energy source and cleaner technology. Methods:: Chrome shavings are hydrolyzed to make collagen paste and mixed with the ferrous nanoparticles of Moringa oleifera leaves and Carbon nanoparticles of Onion peels to form electrolyte paste as base. Then, the electrolyte base was added to the aluminum paste and conducting gel, and mixed well to form composite material for bio-battery. Results:: The composite material of bio-battery has been characterized using Scanning Electron Microscopy (SEM), Fourier-Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) and Thermo Gravimetric Analysis (TGA). Series and parallel circuit testing were done using Copper and Zinc electrodes or Carbon and Zinc electrodes as the battery terminals in the electrolyte paste. The surface area of these electrodes needs standardization from bench to pilot scale. The power generated, for an AA battery size, using a single bio-battery cell has produced a DC voltage of 1.5 V; current of 900 mA. Circuit testing on 1 ml of 80 well-cells connected in series has produced DC output of 18 V and 1100 mA whereas 48 V and 1500 mA were obtained from a series-parallel connection. Conclusion:: The glass transition temperature (Tg) of electrolyte of the bio-battery at 53°C indicates that, at this temperature, all the substances present in the bio-battery are well spread and contributing consistently to the electrolyte activity where Fe-C-Nano-Particles were able to form strong chemical bonds on the flanking hydroxyl group sites of the Collagen leading to reduced mobility of polymers and increase Tg. The results instigate promising trends for commercial exploitation of this composite for bio-battery production.

In-situ stabilization of silver nanoparticles in polymer hydrogels for enhanced catalytic reduction of macro and micro pollutants

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Luqman Ali Shah ◽  
Rida Javed ◽  
Mohammad Siddiq ◽  
Iram BiBi ◽  
Ishrat Jamil ◽  
...  
Keyword(s):  
Catalytic Reduction ◽  
Thermo Gravimetric Analysis ◽  
Activation Parameters ◽  
Reduction Reaction ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
In Situ Stabilization ◽  
Hybrid Hydrogels ◽  
Kinetics Of

AbstractThe in-situ stabilization of Ag nanoparticles is carried out by the use of reducing agent and synthesized three different types of hydrogen (anionic, cationic, and neutral) template. The morphology, constitution and thermal stability of the synthesized pure and Ag-entrapped hybrid hydrogels were efficiently confirmed using scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and thermo gravimetric analysis (TGA). The prepared hybrid hydrogels were used in the decolorization of methylene blue (MB) and azo dyes congo red (CR), methyl Orange (MO), and reduction of 4-nitrophenol (4-NP) and nitrobenzene (NB) by an electron donor NaBH4. The kinetics of the reduction reaction was also assessed to determine the activation parameters. The hybrid hydrogen catalysts were recovered by filtration and used continuously up to six times with 98% conversion of pollutants without substantial loss in catalytic activity. It was observed that these types of hydrogel systems can be used for the conversion of pollutants from waste water into useful products.

scholarly journals Influence of biological origin on the tensile properties of cellulose nanopapers

Cellulose ◽  
2021 ◽  
Author(s):  
Katri S. Kontturi ◽  
Koon-Yang Lee ◽  
Mitchell P. Jones ◽  
William W. Sampson ◽  
Alexander Bismarck ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Cell Wall ◽  
Bacterial Cellulose ◽  
Raw Materials ◽  
Cellulose Nanofibers ◽  
Nanofibrillated Cellulose ◽  
Primary Cell Wall ◽  
Biological Origin ◽  
Basic Principles ◽  
Fiber Mats

Abstract Cellulose nanopapers provide diverse, strong and lightweight templates prepared entirely from sustainable raw materials, cellulose nanofibers (CNFs). Yet the strength of CNFs has not been fully capitalized in the resulting nanopapers and the relative influence of CNF strength, their bonding, and biological origin to nanopaper strength are unknown. Here, we show that basic principles from paper physics can be applied to CNF nanopapers to illuminate those relationships. Importantly, it appeared that ~ 200 MPa was the theoretical maximum for nanopapers with random fibril orientation. Furthermore, we demonstrate the contrast in tensile strength for nanopapers prepared from bacterial cellulose (BC) and wood-based nanofibrillated cellulose (NFC). Endemic amorphous polysaccharides (hemicelluloses) in NFC act as matrix in NFC nanopapers, strengthening the bonding between CNFs just like it improves the bonding between CNFs in the primary cell wall of plants. The conclusions apply to all composites containing non-woven fiber mats as reinforcement. Graphic abstract

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