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Bacterial cellulose
Bacterial cellulose is an organic compound with the formula ) produced from certain types of bacteria. While cellulose is a basic structural material of most plant substances, it is also produced by bacteria, principally of the genera ''Acetobacter'', ''Sarcina ventriculi'' and ''Agrobacterium''. Bacterial, or microbial, cellulose has different properties from plant cellulose and is characterized by high purity, strength, moldability and increased water holding ability. In natural habitats, the majority of bacteria synthesize extracellular polysaccharides, such as cellulose, which form protective envelopes around the cells. While bacterial cellulose is produced in nature, many methods are currently being investigated to enhance cellulose growth from cultures in laboratories as a large-scale process. By controlling synthesis methods, the resulting microbial cellulose can be tailored to have specific desirable properties. For example, attention has been given to the bacteria ''Acetobacter xylinum'' due to its cellulose’s unique mechanical properties and applications to biotechnology, microbiology, and materials science. Historically, bacterial cellulose has been limited to the manufacture of Nata de coco, a South-East Asian food product. With advances in the ability to synthesize and characterize bacterial cellulose, the material is being used for a wide variety of commercial applications including textiles, cosmetics, and food products, as well as medical applications. Many patents have been issued in microbial cellulose applications and several active areas of research are attempting to better characterize microbial cellulose and utilize it in new areas.〔
==History==
As a material, cellulose was first discovered in 1838 by Anselme Payen. Payen was able to isolate the cellulose from the other plant matter and chemically characterize it. In one of its first and most common industrial applications, cellulose from wood pulp was used to manufacture paper. It is ideal for displaying information in print form due to its high reflectivity, high contrast, low cost and flexibility. The discovery of cellulose produced by bacteria, specifically from the ''Acetobacter xylinum'', was accredited to A.J. Brown in 1886 with the synthesis of an extracellular gelatinous mat.〔Brown, A.J. J. Chem. Soc.,49,172, 432(1886);51,643(1887)〕 However, it was not until the 20th century that more intensive studies on bacterial cellulose were conducted. Several decades after the initial discovery of microbial cellulose, C.A. Browne studied the cellulose material obtained by fermentation of Louisiana sugar cane juice and affirmed the results by A.J. Brown.〔Browne, C.A., ''J. Chem. Soc.'', 28, 453 (1906)〕 Other researchers reported the formation of cellulose by other various organisms such as the ''Acetobacter pasteurianum'', ''Acetobacter rancens'', ''Sarcina ventriculi'', and ''Bacterium xylinoides''. In 1931, Tarr and Hibbert published the first detailed study of the formation of bacterial cellulose by conducting a series of experiments to grow A. xylinum on culture mediums.〔Tarr, H.L.A., Hibbery, H. ''Can. J. Research'', 4, 372 (1931)〕
In the mid-1900s, Hestrin et al. proved the necessity of glucose and oxygen in the synthesis of bacterial cellulose. Soon after, Colvin detected cellulose synthesis in samples containing cell-free extract of A. xylinum, glucose and ATP.〔A. Steinbuhel, "Bacterial Cellulose." Biopolymers. Weinheim: Wiley-VCH, 2001. Print.〕 In 1949, the microfibrillar structure of bacterial cellulose was characterized by Muhlethaler. Further bacterial cellulose studies have led to new uses and applications for the material. Some studies have focused on more controlled ways to synthesize microbial cellulose, while other research areas have focused on characterization.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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