Overproduction of bacterial cellulose from Acetobacter xylinum BPR2001 using food industries wastes.

In this study, a cost-effective complex culture media containing molasses and corn steep liquor (CSL) was developed for the high production of bacterial cellulose (BC) by investigating the effect of four effective factors on BC production at three levels using Taguchi and combined methods. The predicted and actual values of BC production in optimal conditions by Taguchi and combined methods were 8.41 and 14.52 g/L, respectively. These results showed that the combined method was more suitable for predicting the optimal conditions in the optimization of BC production, the cost of developed culture medium was around 94% cost of HS medium preparation, molasses was the most effective factor in both experimental design methods, and initial pH adjustment had little impact on BC production. Then, the effect of inoculation conditions containing three factors of inoculation age, ethanol addition time, and agitation rate on the increase of BC production at three levels was investigated using the response surface methodology with the Box-Behnken design algorithm. Under the optimal conditions including inoculum age of 3 days, ethanol addition time of 10 days, and stirring speed of 100 rpm, the predicted and experimental results of BC production were 21.61 and 20.21 g/L, respectively. This is among the highest ever reported for BC production, which was achieved with a more cost-effective culture medium containing molasses and CSL.

Economical Optimization of Industrial Medium Culture for Bacterial Cellulose Production.

The competitiveness of bacterial cellulose (BC) production with plant cellulose can be achieved by production on cost-effective media. It was found that the bacterial cell number ratio of BC to culture medium increases over time so that from the fourth day, the entrapped cell number in the cellulose network exceeds the suspended cells. Optimization based on 23-full factorial showed that inoculum development at 50 rpm and the main culture process under static conditions significantly increases BC production. A cost-effective culture medium containing molasses (ML) and corn steep liquor (CSL) was developed based on the same C/N ratio to HS medium, with 7.24 g/l cellulose at C/N ratio 12.6 is competitive with maximum production 8.7 g/L in HS medium. The BC production cost was reduced about 94% using the proposed cheap and locally available medium containing ML and CSL, while BC mechanical properties increased by about 50%.

Development and evaluation of ciprofloxacin-bacterial cellulose composites produced through in situ incorporation method.

This paper describes the interaction and properties of bacterial cellulose (BC)-ciprofloxacin composites synthesized by in situ incorporation method. Ciprofloxacin's susceptibility to BC's producer, Acetobacter xylinum 0416, was first tested to determine its inhibitory activity against the bacteria. In situ incorporation method was performed by introducing 0.2% (w/v) ciprofloxacin into Hestrin-Schramm medium at the onset of exponential phase of A. xylinum 0416 growth. Following a 10-day incubation at 28 °C, BC-ciprofloxacin composites were harvested and further characterised, while another BC-ciprofloxacin composite was harvested and purified prior to characterisation. The interaction between ciprofloxacin and BC was proven by the presence of quinolines and fluorine groups of ciprofloxacin on unpurified BC-ciprofloxacin composite and the reduction of crystallinity index as compared to the native BC. Moreover, deposited ciprofloxacin crystals on BC film and its composition were exhibited via SEM-Energy-dispersive X-ray analysis. Unpurified BC-ciprofloxacin film was determined to have strongly inhibited the following selected diabetic foot ulcer bacteria: E. coli, K. pneumoniae and P. aeruginosa. BC has the potential to be used as a wound dressing and a carrier for ciprofloxacin.

Characterization of Bacterial Cellulose Produced by Komagataeibacter maltaceti P285 Isolated from Contaminated Honey Wine.

Bacterial cellulose (BC), a biopolymer, is synthesized by BC-producing bacteria. Almost all producing strains are classified in the family Acetobacteraceae. In this study, bacterial strain P285 was isolated from contaminated honey wine in a honey factory in northern Thailand. Based on 16S rRNA gene sequence identification, the strain P285 revealed 99.8% identity with Komagataeibacter maltaceti LMG 1529 T. K. maltaceti P285 produced the maximum BC production at 20-30 °C and an initial media pH of 9.0. The highest BC production in modified mineral salt medium (MSM) was exhibited when glucose (16%, w/v) and yeast extract (3.2%, w/v) were applied as carbon and nitrogen sources, respectively. When sugarcane (8-16%, w/v) or honey (ratio of honey to water = 1: 4) supplemented with yeast extract was used, the BC production was greater. The characterization of BC synthesized by K. maltaceti P285 was undertaken using scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectrometry. Meanwhile, X-ray diffraction results confirmed the presence of crystalline cellulose (2θ = 18.330, 21.390 and 22.640°). The maximum temperature of BC degradation was observed at 314 °C. Tensile properties analysis of hydrated and dried BC showed breaking strength of 1.49 and 0.66 MPa, respectively. These results demonstrated that K. maltaceti P285 has a high potential for BC production especially when grown in high initial media pH. Therefore, the strain would be suitable as an agent to make BC, the value-added product in the related factories.

Self-Grown Bacterial Cellulose Capsules Made through Emulsion Templating.

Microcapsules made of synthetic polymers are used for the release of cargo in agriculture, food, and cosmetics but are often difficult to be degraded in the environment. To diminish the environmental impact of microcapsules, we use the biofilm-forming ability of bacteria to grow cellulose-based biodegradable microcapsules. The present work focuses on the design and optimization of self-grown bacterial cellulose capsules. In contrast to their conventionally attributed pathogenic role, bacteria and their self-secreted biofilms represent a multifunctional class of biomaterials. The bacterial strain used in this work, Gluconacetobacter xylinus, is able to survive and proliferate in various environmental conditions by forming biofilms as part of its lifecycle. Cellulose is one of the main components present in these self-secreted protective layers and is known for its outstanding mechanical properties. Provided enough nutrients and oxygen, these bacteria and the produced cellulose are able to self-assemble at the interface of any given three-dimensional template and could be used as a novel stabilization concept for water-in-oil emulsions. Using a microfluidic setup for controlled emulsification, we demonstrate that bacterial cellulose capsules can be produced with tunable size and monodispersity. Furthermore, we show that successful droplet stabilization and bacterial cellulose formation are functions of the bacteria concentration, droplet size, and surfactant type. The obtained results represent the first milestone in the production of self-assembled biodegradable cellulose capsules to be used in a vast range of applications such as flavor, fragrance, agrochemicals, nutrients, and drug encapsulation.

Bacterial cellulose production by Acetobacter xylinum ATCC 23767 using tobacco waste extract as culture medium.

In this study, bacterial cellulose (BC) was synthesized by Acetobacter xylinum ATCC 23767 using tobacco waste extract (TWE) as a carbon source. Nicotine was found to be an inhibitory factor for BC synthesis, but it can be removed at pH 9.0 by steam distillation. After removing nicotine, the BC production was 2.27 g/L in TWE prepared with solid-liquid (S-L) ratio at 1:10. To further enhance the BC production, two fermentation stages were performed over 16 days by re-adjusting the pH to 6.5 at 7 days, after the first fermentation stage was completed. Using this two-stage fermentation, the BC production could reach 5.2 g/L. Structural and thermal analysis by FE-SEM, FT-IR, XRD and TGA showed the properties of BC obtained from TWE were similar to that from Hestrin-Schramm (HS) medium. Considering the huge disposal tobacco waste in China, the present study provides an alternative methodology to synthesize BC.

Green synthesis of bacterial cellulose via acetic acid pre-hydrolysis liquor of agricultural corn stalk used as carbon source.

Herein, bacterial cellulose (BC) was synthesized by acetobacter xylinum via organic acid pre-hydrolysis liquor of agricultural corn stalk used as carbon source. Acetic acid was applied to pretreat the corn stalk, then, the prehydrolysate was detoxified by sequential steps of activated carbon and ion exchange resin treatment prior to use as carbon source to cultivate acetobacter xylinum. Moreover, the recovery of acetic acid was achieved for facilitating the reduction of cost. The results revealed that the combination method of detoxification treatment was very effective for synthesis of BC, yield could be up to 2.86g/L. SEM analysis showed that the diameter size of BC between 20 and 70mm. In summary, the process that bacterial cellulose was biosynthesized via prehydrolysate from agricultural corn stalk used as carbon source is feasible, and the ability to recover organic acid make it economical, sustainable and green, which fits well into the biorefinery concept.

Luffa sponge offsets the negative effects of aeration on bacterial cellulose production.

AIMS: To offset the negative effects of aeration on bacterial cellulose (BC) production by acetic acid bacteria using enmeshed cellulose microfibrils (CM) on luffa sponge matrices (LSM). METHODS AND RESULTS: The CM were enmeshed on LSM (LSM-CM). The optimal amount of LSM-CM was determined for BC production under aerated conditions. Without LSM-CM, no BC was produced in seven out of nine production cycles at the highest aeration rate (9 l min-1 ). However, with 0·5% LSM-CM and an aeration rate of 3 l min-1 , a satisfactory oxygen transfer coefficient was achieved, and also a good yield of BC (5·24 g l-1 ). Moreover, the LSM-CM was able to be recycled through nine consecutive BC production cycles. The highest BC yields (from 5·8 ± 0·4 to 6·6 ± 0·4 g l-1 ) were associated with high bacterial biomass and this was confirmed by scanning electron microscopy. CONCLUSIONS: We confirm that LSM-CM works well as a starter. Microenvironments low in dissolved oxygen within the matrices of LSM-CM are important for BC production under aeration conditions. SIGNIFICANCE AND IMPACT OF THE STUDY: The LSM-CM provides a microenvironment which offsets the negative effects of aeration on BC production. A sustainable, economic process for mass BC production is described using recycled LSM-CM with aeration.

Microstructured Multilevel Bacterial Cellulose Allows the Guided Growth of Neural Stem Cells.

Repeated photolithographic and etching processes allow the production of multileveled polymer microstructures that can be used as templates to produce bacterial cellulose with defined surfaces on demand. By applying this approach, the bacterial cellulose surface obtains new properties and its use for culturing neural stem cells cellulose substrate topography influences the cell growth in a defined manner.

Antioxidant and anti-inflammatory levan produced from Acetobacter xylinum NCIM2526 and its statistical optimization.

Levan is a homopolymer of fructose naturally obtained from both the plants and microorganisms. Along with the general properties of a biopolymer like bio-compatibility, bio-degradability, renewability, flexibility, and eco-friendliness, levan also offers some important biomedical properties such as anti-oxidant, anti-inflammatory, anti-carcinogenic, anti-AIDS and hyperglycaemic inhibitor. In this study, we have demonstrated the microbial production of therapeutically potential levan by batch fermentation process in sucrose rich medium using Acetobacter xylinum NCIM 2526. The produced Levan was characterized using various physicochemical techniques such as FTIR, (1)H NMR, (13)C NMR spectroscopy, TGA and HPLC. The biomedical potential of the isolated A. xylinum levan for its anti-oxidant and anti-inflammatory activities was exploited in vitro. Further the present study also focused on the optimization of levan production using one factor at a time approach followed by a statistical method, central composite design (CCD) with selected variables. The yield of levan was increased significantly from 0.54 to 13.25g/L with the optimized variables.

Production of nano bacterial cellulose from waste water of candied jujube-processing industry using Acetobacter xylinum.

The work is aimed to investigate the suitability of waste water of candied jujube-processing industry for the production of bacterial cellulose (BC) by Gluconacetobacter xylinum CGMCC No.2955 and to study the structure properties of bacterial cellulose membranes. After acid pretreatment, the glucose of hydrolysate was higher than that of waste water of candied jujube. The volumetric yield of bacterial cellulose in hydrolysate was 2.25 g/L, which was 1.5-folds of that in waste water of candied jujube. The structures indicated that the fiber size distribution was 3-14 nm in those media with an average diameter being around 5.9 nm. The crystallinity index of BC from pretreatment medium was lower than that of without pretreatment medium and BCs from various media had similar chemical binding. Ammonium citrate was a key factor for improving production yield and the crystallinity index of BC.

Agarose particle-templated porous bacterial cellulose and its application in cartilage growth in vitro.

Bacterial cellulose (BC) is a biocompatible hydrogel with a three-dimensional (3-D) structure formed by a dense network of cellulose nanofibers. A limitation of using BC for applications in tissue engineering is that the pore size of the material (∼0.02-10µm) is smaller than the dimensions of mammalian cells and prevents cells from penetrating into the material and growing into 3-D structures that mimic tissues. This paper describes a new route to porous bacterial cellulose (pBC) scaffolds by cultivating Acetobacter xylinum in the presence of agarose microparticles deposited on the surface of a growing BC pellicle. Monodisperse agarose microparticles with a diameter of 300-500µm were created using a microfluidic technique, layered on growing BC pellicles and incorporated into the polymer as A. xylinum cells moved upward through the growing pellicle. Removing the agarose microparticles by autoclaving produced BC gels containing a continuous, interconnected network of pores with diameters ranging from 300 to 500µm. Human P1 chondrocytes seeded on the scaffolds, replicated, invaded the 3-D porous network and distributed evenly throughout the substrate. Chondrocytes grown on pBC substrates displayed a higher viability compared to growth on the surface of unmodified BC substrates. The approach described in this paper introduces a new method for creating pBC substrates with user-defined control over the physical dimensions of the pore network, and demonstrates the application of these materials for tissue engineering.

Green synthesis of silver and gold nanoparticles employing levan, a biopolymer from Acetobacter xylinum NCIM 2526, as a reducing agent and capping agent.

With a vision of finding greener materials to synthesize nanoparticles, we report the production and isolation of levan, a polysaccharide with repeating units of fructose, from Acetobacter xylinum NCIM2526. The isolated levan were characterized using potassium ferricyanide reducing power assay, Fourier transform infra-red (FTIR) spectroscopy and (1)H nuclear magnetic resonance spectroscopy ((1)H NMR). To exploit levan in nanotechnology, we present a simple and greener method to synthesize silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) using biopolymer, levan as both reducing and stabilizing agents. The morphology and stability of the AgNPs and AuNPs were examined by transmission electron microscopy (TEM) and UV-vis absorption (UV-vis) spectroscopy. The possible capping mechanism of the nanoparticles was postulated using FTIR studies. As synthesized biogenic nanoparticles showed excellent catalytic activity as evidenced from sodium borohydride mediated reduction of 4-nitro phenol and methylene blue.

Nisin based stabilization of novel fruit and vegetable functional juices containing bacterial cellulose at ambient temperature.

The current study reports the preparation and stabilization of novel functional drinks based on fruit and vegetable juices incorporating bacterial cellulose from Acetobacter xylinum. Pineapple, musk melon, carrot, tomato, beet root and a blend juice containing 20 % each of carrot and tomato juice with 60 % beet root juice has been studied. These juices have been stabilized over a storage period of 90 days at 28 °C, by the use of nisin and maintaining a low pH circumventing the need for any chemical preservatives or refrigeration. Instrumental color values have been correlated with the pigment concentrations present in the fresh as well as stored juices. There was 36, 72 and 60 % loss of total carotenoids in the case of carrot, pineapple and musk melon juices respectively while the lycopene content remained unchanged after 90 days of storage. The betanin content decreased 37 % in the case of beetroot juice and 25 % in the case of beetroot juice blended with carrot and tomato juices. Sensory analysis has revealed a clear preference for the beetroot blended mixed juice.

Minerals consumption by Acetobacter xylinum on cultivation medium on coconut water.

The objective of this work is to verifying the consume of the minerals K, Na, Fe, Mg, P, S-SO4 (-2), B, N Total Kjedahl (NTK), NO3 (-)-N, and NH4 (+)-N in the production of bacterial cellulose by Acetobacter xylinum, according to the medium and the manner of cultivation. The fermentative process was in ripe and green coconut water. K and Na were determined by flame emission photometry, Mg and Fe by atomic absorption spectrophotometry, P by molecular absorption spectrophotometry, S-SO4 (-2) by barium sulphate turbidimetry, B by Azomethin-H method, NTK by Kjeldahl method, N-NO3 (-) and N-NH4 (+) by vapor distillation with magnesium oxide and Devarda's alloy, respectively. In Fermentation of ripe coconut water there were higher consumption of K (69%), Fe (84,3%), P (97,4%), S-SO2 (-2) (64,9%), B (56,1%), N-NO3 (-) (94,7%) and N-NH4 (+) (95,2%), whereas coconut water of green fruit the most consumed ions were Na (94,5%), Mg (67,7%) and NTK (56,6%). The cultivation under agitation showed higher mineral consumption. The higher bacterial cellulose production, 6 g.L(-1), was verified in the coconut water fermentative in ripe fruit, added KH2PO4, FeSO4 and NaH2PO4 kept under agitation.

Minerals consumption by Acetobacter xylinum on cultivation medium on coconut water

The objective of this work is to verifying the consume of the minerals K, Na, Fe, Mg, P, S-SO4-2,B,N Total Kjedahl (NTK), NO3--N, and NH4+-N in the production of bacterial cellulose by Acetobacter xylinum, according to the medium and the manner of cultivation. The fermentative process was in ripe and green coconut water. K and Na were determined by flame emission photometry, Mg and Fe by atomic absorption spectrophotometry, P by molecular absorption spectrophotometry, S-SO4-2 by barium sulphate turbidimetry, B by Azomethin-H method, NTK by Kjeldahl method, N-NO3-and N-NH4+ by vapor distillation with magnesium oxide and Devarda's alloy, respectively. In Fermentation of ripe coconut water there were higher consumption of K (69%), Fe (84,3%), P (97,4%), S-SO2-2 (64,9%), B (56,1%), N-NO3 (94,7%) and N-NH4+ (95,2%), whereas coconut water of green fruit the most consumed ions were Na (94,5%), Mg (67,7%) and NTK (56,6%). The cultivation under agitation showed higher mineral consumption. The higher bacterial cellulose production, 6 g.L-1, was verified in the coconut water fermentative in ripe fruit, added KH2PO4, FeSO4 and NaH2PO4 kept under agitation.

The Characterization of Acetic Acid Bacteria Efficiently Producing Bacterial Cellulose from Sucrose: The Proposal of Acetobacter xylinum subsp. nonacetoxidans subsp. Nov.

A taxonomic study was done for the isolates obtained as cellulose high producers from sucrose. These strains were found to have a common characteristic unique for Acetobacter; they did not oxidize acetate and lactate. Therefore, we concluded that these isolates are classified as a new subspecies and proposed Acetobacter xylinum subsp. nonacetoxidans subsp. nov. BPR 2002 (=JCM 10150) was designated as a type strain of the new subspecies.

Acetobacter xylinum Mutant with High Cellulose Productivity and an Ordered Structure.

Acetobacter xylinum subsp. sucrofermentans BPR2001, a cellulose-producing bacterium, that was newly isolated from a natural source, produced large amounts of the water-soluble polysaccharide, acetan. UDP-glucose is known to be the direct precursor in the synthetic pathways of both cellulose and acetan. We attempted to breed mutant strains and succeeded in obtaining one, BPR3001A, which produced 65% more bacterial cellulose and accumulated 83% less acetan than the parent strain, BPR2001. The cellulose formed was found to be structurally ordered, with higher degrees of polymerization and crystallinity and larger crystallite size than those produced by BPR2001 and other conventional strains. Furthermore, a processed dry sheet of this cellulose exhibited a higher Young's modulus than that of the wild strain. The ordered structure of the cellulose obtained was probably due to the decreased amount of acetan which may reflect the ribbon assembly of cellulose fibrils without prevention of hydrogen bonding between microfibrils.

A Novel Type of D-Mannitol Dehydrogenase from Acetobacter xylinum: Occurrence, Purification, and Basic Properties.

We purified a novel type of D-mannitol dehydrogenase, which contains a c-type cytochrome and an unknown chromophore in the soluble fraction of an acetic acid bacterium, Acetobacter xylinum KU-1, to homogeneity. The enzyme showed the maximum activity at pH 5 and 40°C. It was stable up to 60°C at pH 6, and was inhibited by Hg(2+) and p-quinone (Ki = 0.18 mm). The molecular weight of the enzyme was about 140,000, and those of the subunits were 69,000, 51,000, and 20,000; the enzyme is hetero-trimeric and contained 8 g-atoms of Fe per mole. The α-helix content was estimated to be about 52.9%. The enzyme catalyzed phenazine methosulfate dependent oxidation of d-mannitol with an apparent Km of 98 µm (for d-mannitol) and Vmax of 213 µmol/min/mg. The reduced form of the enzyme showed the absorption maxima at 386, 416, 480, 518, 550, and 586 nm, which are attributable to a c-type cytochrome in the enzyme.

Optimum Culture Conditions for Bacterial Cellulose Produced by Acetobacter xylinum NUST4 / 微生物学通报

The optimum culture conditions for Acetobacter xylinum NUST4 which produces bacterial cellulose(BC) were obtained by uniform design method.BC production was dependent on MgSO_(4)?7H_(2)O,FeSO_(4)?7H_(2)O and cosubstrates such as p-aminobenzoic acid,nicotinamide,d-Biotin and ethanol.The optimal medium contained glucose 24g,sucrose 22g,peptone 16g,HAc 2.4mL,Na_(2)HPO_(4)?12H_(2)O 3.5 g,KH_(2)PO_(4)?H_(2)O 1 g,MgSO_(4)?7H_(2)O 6 g,FeSO_(4)?7H_(2)O 0.015g,nicotinamide 0.003 g,d-Biotin 0.02g and ethanol 20mL in 1L culture medium.BC yield reached 9.87g(the dried weight) in stationary culture for 7 days,which was 12-fold higher than that in the S-H medium.