Acetobacter xylinum, cellulose

Tobacco primary cell wall and normal bacterial Acetobacter xylinum cellulose formation produced a 36.8 3A triple-stranded left-hand helical microfibril in freeze-dried Pt-C replicas and in negatively stained preparations for transmission electron microscopy (TEM). A. xylinum growth in the presence of 0.25 mM Tinopal disrupted cellulose microfibril formation and produced a... 

The kind of polysaccharides that are isolated from different bacteria are as follows Alginate, a linear copolymer with (l-4)-linked p-D-mannuronate and its a-L-guluronate residues that is produced by two bacterial genera Pseudomonas species and Azotobacter vinelandii [4]. Bacterial alginates are useful for the production of micro- or nanostructures suitable for medical applications. Cellulose, a p (1—>4) linked D-glucose unit obtained from Acetobacter xylinum. Cellulose of plant origin is usually impure as it contains... 

Iwata, T., Indrarti, L., Azuma, J., 1998. Affinity of hetnicellulose for cellulose produced by Acetobacter xylinum. Cellulose 5, 215—228. 

Romano, M., Franzosi, G., Seves, A., Sora, S., 1989. Study of the production of cellulose gel and cellulose by Acetobacter xylinum. Cellulose Chemistry and Technology 23, 217—223. 

George J, Ramana KV, Bawa AS, Siddaramaiah (2011) Bacterial eellulose nanoerystals exhibiting high thermal stability and their polymer nanocomposites. Ind J Biol Macromol 48(l) 50-57 George J, Ramana KV, Sabapathy SN, Bawa AS (2005a) Physieo-mechanieal properties of chemically treated bacterial (Acetobacter xylinum) cellulose membrane. World J Mierobiol Biotechnol 21 (8-9) 1323-1327... 

In 1886, Brown11 discovered an organism which formed extremely tough membranes when cultivated m suitable nutrient solutions containing carbohydrates such as D-fructose, D-mannitol or D-glucose ethanol, sucrose or starch did not support membrane formation by this organism which Brown called Bacterium xylinum ) (Acetobacter xylinum). The membranes were readily soluble in cuprammonium hydroxide solution and yielded a dextrorotatory sugar upon acid hydrolysis. These properties and the results of combustion analysis led him to believe that the membrane was cellulose. 

Isolation and sequencing of the cellulose synthase gene(s) has not been accomplished yet however, DNA from Acetobacter xylinum containing this gene(s) was cloned into broad host-range plasmid vectors (82). These vectors were mobilized into Pel- mutants to test for complementation. To date, this approach has not produced a pellicle-forming transconjugant from a Pel- mutant of Acetobacter (82). The direct correlation between cellulose production and presence of plasmid DNA in Acetobacter has been reported... 

Triple-Stranded Left-Hand Helical Cellulose Microfibril in Acetobacter xylinum and in Tobacco Primary Cell Wall... 

The gram negative bacterium Acetobacter xylinum produces a ribbon of crystalline cellulose I whose neutral sugar content is 96.8% glucose and 3.2% xylose (1). Growth of A. xylinum in a medium containing... 

The bacterial cellulose synthase from Acetobacter xylinum can be solubilized with detergents, and the resulting enzyme generates characteristic 1.7 ran cellulose fibrils (Fig. 20-4) from UDP-glucose.125/127-129 These are similar, but not identical, to the fibrils of cellulose I produced by intact bacteria.125 130 Each native fibril appears as a left-handed helix which may contain about nine parallel chains in a crystalline array. Three of these helices appear to coil together (Fig. 20-4) to form a larger 3.7-nm left-handed helical fibril. Similar fibrils are formed by plants. In both... 

The reducing end groups in cellulose are the only naturally occurring carbonyl functionalities in this material. Cellulose from Acetobacter xylinum [43] contains an amount of carbonyl groups which corresponds approximately to the number of reducing end groups, and can be considered as rather genuine material. 

Fig. I.—Proposed Model of Cellulose Assembly in Acetobacter xylinum. [d-GIu-can chain aggregates from organized, multiple-enzyme complexes, and extrusion pores crystallize into microfibrils, which then assemble into bundles and the normal ribbon at the cell surface.]...

Fig. 3,—Pulse-chase Experiment with Acetobacter xylinum.10 Incorporation of D-[14C]glucose (3,300 c.p.m. per nmol) into the water- and alkali-soluble fractions, and its subsequent transfer from these fractions into cellulose. In the pulse, cells were incubated in 3 mM D-[14C]glucose at 0° in buffer at pH 6.0 at the time of the chase, cells were diluted in cold buffer, centrifuged, and re-incubated at 30° in buffer either containing 40 mM unlabeled D-glucose (-) or lacking D-glucose (—). ...

It is thus very likely that at least cellulose produced by Acetobacter xylinum is synthesized by simultaneous polymerization and crystallization. Especially interesting remaining problems in this system are the questions of nucleation of new fibrils, the reasons for the limiting diameter of the fibrils, and the defect structure of the only partially crystalline cellulose which is not uniform across the fibril. 

The cellulose 4-p-glucosyltransferase of Acetobacter xylinum exhibits 42.8 % identity at the DNA level and 26.2 % identity at the whole deduced amino add level to the pcs A2 polypeptide. The cotton cel Al polypeptide exhibits 53.9 % identity at the DNA level and 68.7 % identity at the amino add level to the pcs A2 polypeptide. The hydropathy profiles suggest at least two transmembrane helices, e.g., one is located in the N-terminal region and one is in C-terminal region. The central regions of the polypeptides are rather hydrophilic and are... 

Conversion of CO2 into cellulose by gene manipulation of microalgae Cloning of cellulose synthase genes from Acetobacter xylinum... 

Hestrin S, Schramm M (1954) Synthesis of cellulose by Acetobacter xylinum preparation of freeze dried cells capable of polymerizing glucose to cellulose. Biochem J 58 345... 

Disaccharide fluorides have been treated with cellulase to produce cellulose, amylose, and xylan.316 A mutant strain of Acetobacter xylinum produced cellulose that imparted higher tensile strength and superior properties to paper than did cellulose from higher plants.317 An economical mass production technique has been devised for it. 

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