A novel static cultivation of bacterial cellulose production from sugar beet molasses: Series static culture (SSC) system.

In bacterial cellulose (BC) production, we developed a new static cultivation system named series static culture (SSC) to eliminate air limitation problem encountered in conventional static culture (CSC). In SSC system, the fermentation broth at the bottom of BC pellicle produced in initial culture medium is transferred to the next empty sterile culture medium at the end of a certain fermentation period. This procedure was performed until BC production ceased. Fermentation experiments were carried out using Gluconacetobacter xylinus NRRL B-759 and sugar beet molasses at 30 °C and initial pH 5. Also, some quality parameters of produced BC pellicles were determined. Final pH at the stages of SSC system was higher that of the initial pH due to sugar content (sucrose) of molasses and microorganism used. Total BC production increased with increasing sugar concentration in SSC. As a result, an increase of 22.02 % in BC production was achieved using developed SSC. FT-IR spectra of all BC pellicles produced were typical spectra. The absorption bands at the relevant wavenumbers identify the mode of vibrations of the created chemical bonds arising at the BC surface such as OH, CH, H-O-H, C-O-C, and C-OH. XRD analyses showed that the crystallinity index values of BC obtained from CCS and SSC were high. The form of produced all BC pellicles is generally Cellulose I. Removal of surface moisture and depolymerisation of carbon skeleton were determined from TGA-DTA thermograms. SEM images showed that the BC samples produced had nano-sized cellulose fibrils which were aggregated in fermentation media containing molasses. Finally, the BC samples, especially in molasses media, having high mechanical strength and WHC were found.

Stoichiometric Analysis and Production of Bacterial Cellulose by Gluconacetobacter liquefaciens using Borassus flabellifer L. Jaggery.

The objective of the work is to examine the potential utilization of Palmyra palm jaggery (PPJ) for the enhancement of bacterial cellulose (BC) production by Gluconacetobacter liquefaciens. To evaluate the culturing condition, the production of BC fermentation was carried out in batch mode using different carbon sources namely glucose, sucrose and PPJ. PPJ in the HS medium (PHS medium) resulted maximum concentration of BC (14.35 ± 0.18 g/L) under shaking condition than other carbon sources in HS medium. The influence of different medium variables including initial pH and nitrogen sources on BC production was investigated using PHS medium under shaking condition. The maximum BC concentration of 17.79 ± 2.4 g/L was obtained in shaking condition at an initial pH of 5.6 using yeast extract as nitrogen source. Stoichiometric equation for the cell growth and BC synthesis was developed using elemental balance approach. The metabolic heat of reaction (40 kcal generated per liter of medium) was evaluated using electron balance approach. Based on the process economic analysis and the yield of BC during the fermentation, PHS medium without nitrogen source could be a promising cost-effective nutrient than HS medium. Thermal stability, crystallinity index and structural characterizations of produced BC using PPJ medium were evaluated using TGA, XRD and FTIR and the obtained results were compared with HS medium containing glucose and sucrose.

Characterization of Bacterial Cellulose Produced by Acetobacter xylinum Strain LKN6 Using Sago Liquid Waste as Nutrient Source.

<b>Background and Objective:</b> Bacterial Cellulose (BC) is an exopolysaccharide produced by bacteria with unique structural and mechanical properties and is highly pure compared to plant cellulose. This study aimed to produce novel bacterial cellulose using sago liquid waste substrate and evaluate its characteristics as a potential bioplastic.<b>Materials and Methods:</b> Production of BC by static batch fermentation was studied in sago liquid waste substrate usingAcetobacter xylinumLKN6. The BC structure was analyzed by Scanning Electron Microscopy (SEM) and Fourier Transform infrared spectroscopy (FT-IR). Mechanical properties were measured include tensile strength, elongation at break, elasticity (Young's modulus) and Water Holding Capacity (WHC). <b>Results:</b> The BC yield from sago liquid waste as a nutrients source was achieved 12.37 g L¹ and the highest BC yield 14.52 g L¹ in sago liquid waste medium with a sugar concentration of 10% (w/v) after 14 days fermentation period. The existence of bacterial cellulose is proven by FT-IR spectroscopy analysis based on the appearance of absorbance peaks, which are C-C bonding, C-O bonding, C-OH bonding and C-O-C bonding and represents the fingerprints of pure cellulose. The mechanical properties of BC from sago liquid waste were showed a tensile strength of 44.2-87.3 MPa, elongation at break of 4.8-5.8%, Young's Modulus of 0.86-1.64 GPa and water holding capacity of 85.9-98.6 g g¹. <b>Conclusion:</b> The results suggest that sago liquid waste has great potential to use as a nutrient source in the production of bacterial cellulose and BC's prospect as the bioplastic.

Response surface methodology-based improvement of the yield and differentiation of properties of bacterial cellulose by metabolic enhancers.

This study aims to examine the effect of ethanol and lactic acid on the production of bacterial cellulose, and determine the optimal composition of a co-supplemented culture using response surface methodology. Both ethanol and lactic acid, when added separately or jointly, affected the yield and properties of the biomaterial. Optimization resulted in an increase of 470% in the yield, compared to the Schramm-Hestrin medium. Culture growth profiles, substrate consumption and by-products generation, were examined. The growth rate was increased for cultures supplemented with lactic acid and both lactic acid and ethanol, while the production of gluconic acid was diminished for all modified cultures. The properties of BNC, such as the structure, crystallinity, water holding capacity and tensile strength, were also determined. BNC produced in optimal conditions is more porous and characterized by wider fibers. Despite a decrease in crystallinity, by the addition of ethanol, lactic acid and both additives, the ratio of cellulose Iα was almost unchanged. The stress, strain, young modulus and toughness were improved 2.8-4.2 times, 1-1.9 times, 2.4-3.5 times and 2.5-6.8 times, respectively. The new approach to improving BNC yields and properties presented here could contribute to more economical production and wider application of this biopolymer.

AgNPs Ornamented Modified Bacterial Cellulose Based Self-Healable L-B-L Assembly via a Schiff Base Reaction: A Potential Wound Healing Patch.

A layer-by-layer (L-B-L) bacterial cellulose (BC)-based transdermal patch has been prepared via a Schiff base reaction. The L-B-L assembly consisting of covalently cross-linked ethylene diamine-modified carboxymethylated BC isolated from the Glucanoacetobacter xylinus (MTCC7795) bacterial strain and aldehyde-modified pectin formed via a Schiff base reaction. The presence of the imine bond assists the self-healing process after being scratched in the presence of a pH 7.4 buffer solution monitored via optical microscopy, atomic force microscopy, and tensile strength analyses. The formation of the L-B-L assembly was confirmed using field-emission scanning electron microscopy (FESEM) analysis. Simultaneously, water swelling and deswelling studies were carried out to test its water retention efficiency. The presence of silver nanoparticles (AgNPs) has been confirmed by ultraviolet-visible spectroscopy and FESEM analyses. The antimicrobial activity of the AgNPs-incorporated transdermal patch has been examined over Staphylococcus aureus and Escherichia coli using the zone of inhibition method. Additionally, the cell viability assay was performed using the fluorescent dyes 4',6-diamidino-2-phenylindole and propidium iodide. The AgNPs in the L-B-L assembly showed antimicrobial property against both types of bacteria. The cytotoxicity and wound healing property of the patch system have been studied over NIH 3T3 fibroblast and A549 epithelial cell lines. The L-B-L film also influenced the wound healing process of these two cell lines.

Ecofriendly green conversion of potato peel wastes to high productivity bacterial cellulose.

Potato peel waste (PPW) is employed as the first report on bacterial cellulose (BC) production by Gluconacetobacter xylinus. Scharification of PPW was performed by 2 M different mineral acids individually. The suitable pre-treatment conditions were determined by reducing sugar release. Although all acid PPW-hydrolysates culture media are studied to produce BCs. Nitric acid hydrolysate gives the high productivity value The influence of nitric acid PPW-hydrolysate culture condition parameters were applied throughout the Taguchi method and the optimum conditions for the highest BC yield (4.7 g/L) was observed after 6 days at 35 °C, pH 9, medium volume 55 ml and with 8% inoculum size. The instrumental analysis of PPW-BC, included FT-IR, Particle size distribution, BET, DSC, XRD and SEM are cleared that the PPW-BC recorded high crystalliny82.5%, excellent PDI. In general, this study revealed that nitric acid PPW-hydrolysate could be used as cost effective alternative medium for production of BC with sustainable processes that can overcome the environmental pollution.

Preparation and characterization of cellulose nanocrystals from bacterial cellulose produced in sugar beet molasses and cheese whey media.

Bacterial cellulose (BC) is gaining considerable attention due to its unique physicochemical and mechanical properties. In this study, BC production by Gluconacetobacter xylinus PTCC 1734 in sugar beet molasses, cheese whey and standard Hestrin-Schramm (HS) media was evaluated. The synthesized BC was hydrolyzed by sulfuric acid to prepare bacterial cellulose nanocrystals (BCNC). The results showed that treated sugar beet molasses led to the highest BC concentration and productivity, followed by treated cheese whey. Structural analysis of BC and BCNC was carried out by Fourier Transform Infrared (FTIR) spectroscopy. The crystallinity index of the BCNC determined by X-ray diffraction (XRD) was higher than BC. The morphological analysis carried out by FE-SEM showed that microfibrils diameter decreases with acid treatment. TEM images confirmed the formation of rod like cellulose nanocrystals having an average diameter and length of 25 ±â€¯5 and 306 ±â€¯112 nm, respectively. In conclusion, food industrial byproducts can be used as cost-effective culture media to produce BC for large-scale industrial production and isolated cellulose nanocrystals are useful in the fabrication of bio-nanocomposite films for food packaging applications.

Aluminium effects on mechanical properties of cell wall analogues.

Aluminium (Al) toxicity adversely impacts plant productivity in acid soils by restricting root growth and although several mechanisms are involved the physiological basis of decreased root elongation remains unclear. Understanding the primary mechanisms of Al rhizotoxicity is hindered due to the rapid effects of soluble Al on root growth and the close proximity of many cellular components within the cell wall, plasma membrane, cytosol and nucleus with which Al may react. To overcome some of these difficulties, we report on a novel method for investigating Al interactions with Komagataeibacter xylinus bacterial cellulose (BC)-pectin composites as cell wall analogues. The growth of K. xylinus in the presence of various plant cell wall polysaccharides, such as pectin, has provided a unique in vitro model system with which to investigate the interactions of Al with plant cell wall polysaccharides. The BC-pectin composites reacted in a similar way with Al as do plant cell walls, providing insights into the effects of Al on the mechanical properties of the BC-pectin composites as cell wall analogues. Our findings indicated that there were no significant effects of Al (4-160 µM) on the tensile stress, tensile strain or Young's modulus of the composites. This finding was consistent with cellulose, not pectin, being the major load bearing component in BC-pectin composites, as is also the case in plant cell walls.

Bacterial cellulose production from the litchi extract by Gluconacetobacter xylinus.

Although litchi has both nutrient and edible value, the extremely short preservation time limited its further market promotion. To explore processed litchi products with longer preservation time, litchi extract was selected as an alternative feedstock for production of bacterial cellulose (BC). After 2 weeks of static fermentation, 2.53 g/L of the BC membrane was obtained. The trace elements including magnesium (Mg) and sodium (Na) in the litchi extract were partly absorbed in the BC membrane, but no potassium (K) element was detected in it, curiously. Scanning electron microscope (SEM) photographs exhibited an ultrafine network nanostructure for the BC produced in the litchi extract. Analysis of the fourier-transform infrared spectroscopy (FTIR) confirmed the pellicles to be a cellulosic material. Interestingly, X-ray diffraction (XRD) results showed the BC membrane obtained from litchi extract had higher crystallinity of 94.0% than that from HS medium. Overall, the work showed the potential of producing high value-added polymer from litchi resources.

Binding of arabinan or galactan during cellulose synthesis is extensive and reversible.

Arabinans and galactans are major components of the side-chains of pectin in plant cell walls. In order to understand how pectin side-chains interact with cellulose, in this work we studied the interaction of de-branched arabinan (from sugar beet) and linear galactan (from potato) during the synthesis of cellulose by Gluconacetobacter xylinus (ATCC 53524) to mimic in muro assembly. The binding studies reveal that arabinan and galactan are able to bind extensively (>200mg/g of cellulose) during cellulose deposition, and more than pectin (from apple) in the absence of calcium. (13)C NMR revealed that associated arabinan, galactan or apple pectin molecules were neither rigid nor affected cellulose crystallinity, and there was no apparent change in cellulose architecture as reflected in scanning electron micrographs. De-binding of arabinan, galactan or apple pectin occurred as a result of washing, indicating a reversible binding to cellulose, which was modelled in terms of a surface-controlled process. Implications for structural models of primary plant cell walls and possible roles for cellulose binding of arabinan- and galactan-rich pectins in biological processes are discussed.

Occurrence of Cellulose-Producing Gluconacetobacter spp. in Fruit Samples and Kombucha Tea, and Production of the Biopolymer.

Cellulose producing bacteria were isolated from fruit samples and kombucha tea (a fermented beverage) using CuSO4 solution in modified Watanabe and Yamanaka medium to inhibit yeasts and molds. Six bacterial strains showing cellulose production were isolated and identified by 16S rRNA gene sequencing as Gluconacetobacter xylinus strain DFBT, Ga. xylinus strain dfr-1, Gluconobacter oxydans strain dfr-2, G. oxydans strain dfr-3, Acetobacter orientalis strain dfr-4, and Gluconacetobacter intermedius strain dfr-5. All the cellulose-producing bacteria were checked for the cellulose yield. A potent cellulose-producing bacterium, i.e., Ga. xylinus strain DFBT based on yield (cellulose yield 5.6 g/L) was selected for further studies. Cellulose was also produced in non- conventional media such as pineapple juice medium and hydrolysed corn starch medium. A very high yield of 9.1 g/L cellulose was obtained in pineapple juice medium. Fourier transform infrared spectrometer (FT-IR) analysis of the bacterial cellulose showed the characteristic peaks. Soft cellulose with a very high water holding capacity was produced using limited aeration. Scanning electron microscopy (SEM) was used to analyze the surface characteristics of normal bacterial cellulose and soft cellulose. The structural analysis of the polymer was performed using (13)C solid-state nuclear magnetic resonance (NMR). More interfibrillar space was observed in the case of soft cellulose as compared to normal cellulose. This soft cellulose can find potential applications in the food industry as it can be swallowed easily without chewing.

Formation of cellulose-based composites with hemicelluloses and pectins using Gluconacetobacter fermentation.

Gluconacetobacter xylinus synthesises cellulose in an analogous fashion to plants. Through fermentation of Ga. xylinus in media containing cell wall polysaccharides from the hemicellulose and/or pectin families, composites with cellulose can be produced. These serve as general models for the assembly, structure, and properties of plant cell walls. By studying structure/property relationships of cellulose composites, the effects of defined hemicellulose and/or pectin polysaccharide structures can be investigated. The macroscopic nature of the composites also allows composite mechanical properties to be characterised. The method for producing cellulose-based composites involves reviving and then culturing Ga. xylinus in the presence of desired hemicelluloses and/or pectins. Different conditions are required for construction of hemicellulose- and pectin-containing composites. Fermentation results in a floating mat or pellicle of cellulose-based composite that can be recovered, washed, and then studied under hydrated conditions without any need for intermediate drying.

Metal ion effects on hydraulic conductivity of bacterial cellulose-pectin composites used as plant cell wall analogs.

Low concentrations of some trace metals markedly reduce root elongation rate and cause ruptures to root rhizodermal and outer cortical cells in the elongation zone. The interactions between the trace metals and plant components responsible for these effects are not well understood but may be linked to changes in water uptake, cell turgor and cell wall extensibility. An experiment was conducted to investigate the effects of Al, La, Cu, Gd, Sc and Ru on the saturated hydraulic conductivity of bacterial cellulose (BC)-pectin composites, used as plant cell wall analogs. Hydraulic conductivity was reduced to approximately 30% of the initial flow rate by 39 microM Al and 0.6 microM Cu, approximately 40% by 4.6 microM La, 3 microM Sc and 4.4 microM Ru and approximately 55% by 3.4 microM Gd. Scanning electron microscopy (SEM) revealed changes in the ultrastructure of the composites. The results suggest that trace metal binding decreases the hydraulic conductivity through changes in pectin porosity. The experiment illustrates the importance of metal interactions with pectin, and the implications of such an interaction in plant metal toxicity and in normal cell wall processes.

Engineering microporosity in bacterial cellulose scaffolds.

The scaffold is an essential component in tissue engineering. A novel method to prepare three-dimensional (3D) nanofibril network scaffolds with controlled microporosity has been developed. By placing paraffin wax and starch particles of various sizes in a growing culture of Acetobacter xylinum, bacterial cellulose scaffolds of different morphologies and interconnectivity were prepared. Paraffin particles were incorporated throughout the scaffold, while starch particles were found only in the outermost area of the resulting scaffold. The porogens were successfully removed after culture with bacteria and no residues were detected with electron spectroscopy for chemical analysis (ESCA) or Fourier transform infra-red spectroscopy (FT-IR). Resulting scaffolds were seeded with smooth muscle cells (SMCs) and investigated using histology and organ bath techniques. SMC were selected as the cell type since the main purpose of the resulting scaffolds is for tissue engineered blood vessels. SMCs attached to and proliferated on and partly into the scaffolds.

Utilization of the buffering capacity of corn steep liquor in bacterial cellulose production by Acetobacter xylinum.

Acetobacter xylinum BPR2001 produces water-insoluble bacterial cellulose (BC). Using a pH sensor for the accurate control of pH, which is one of the most critical factors for efficient BC production, is difficult especially in a baffled shake-flask and an airlift reactor. The buffering capacity of corn steep liquor (CSL) was estimated by measuring beta (buffering capacity) values in advance and was used to maintain the pH within the optimal range during the production of BC. When CSL was added to either a shake-flask, a stirred-tank reactor or an airlift reactor, BC production was almost the same as that in cultivations where pH was controlled manually or by a pH sensor.

Tensile deformation of bacterial cellulose composites.

The polymeric basis for the mechanical properties of primary plant cell walls has been investigated by forming analogous composites based on fermentation of the bacterium Acetobacter xylinus, either alone or in the presence of xyloglucan or pectin. Simultaneous small-angle X-ray scattering and uniaxial deformation experiments has shown how the cellulose microfibrils reorient during deformation. Despite very different stress/strain curves, the reorientation behaviour is similar, regardless of the presence or absence of xyloglucan or pectin. A simple theory has been developed to predict the orientation behaviour. This is qualitatively similar to the measured behaviour, but differs quantitatively.