Cellulose and other capsular polysaccharides of acetic acid bacteria

Abstract

Some acetic acid bacteria including Komagataeibacter xylinus are known to produce a large amount of cellulose in their culture media. This bacterial cellulose has a unique structure. The fiber of bacterial cellulose is ultrafine, with a width approximately 1/1000th that of pulp cellulose. Although the mechanism of bacterial cellulose synthesis is unclear, recent research, including structure analysis by X-ray diffraction, has revealed the mechanism at the cellulose synthase complex. The biological function of bacterial cellulose, as well as other capsular polysaccharides of acetic acid bacteria, seems to be the formation of biofilms that allow the retention of bacterial cells on the culture surface. This mechanism is favorable for their survival because acetic acid bacteria are strictly oxidative and utilize a large amount of oxygen for their metabolism. To use bacterial cellulose as a commodity material, industrial production systems have been developed using strain improvement and agitation cultures. Bacterial cellulose has many unique properties derived from its structural features. In addition to having been utilized for a long time as a well-known dessert (nata de coco) in Southeast Asia, it has many other possible applications. Some of these have already been commercialized, including speaker diaphragms and artificial skin.