Bacterial Cellulose Production: Biosynthesis and Applications
Svein Valla, Helga Ertesvåg, Naoto Tonouchi and Espen Fjaervik
from: Microbial Production of Biopolymers and Polymer Precursors: Applications and Perspectives (Edited by: Bernd H. A. Rehm). Caister Academic Press, U.K. (2009)
Gluconacetobacter xylinus (formerly Acetobacter xylinum) has for technical reasons been a favorite model system used for studies of the biochemistry and genetics of cellulose biosynthesis, even though the vast majority of the polymer is produced by green land-plants. Structurally cellulose is a simple polysaccharide, in that it consists only of one type of sugar (glucose), and the units are linearly arranged and linked together by β-1,4 linkages only. The mechanism of biosynthesis is however rather complex, partly because in native celluloses the chains are organized as highly ordered water-insoluble fibers. Currently the key genes involved in cellulose biosynthesis and regulation are known in a number of bacteria, but many details of the biochemistry of its biosynthesis are still not clear. A survey of genome sequence databases clearly indicates that a very large number of bacteria have the genes needed to produce cellulose, and this has also been experimentally confirmed for a smaller number of organisms. The biological functions of bacterial celluloses vary among species, and range from a role as a floating device to involvement in plant root adhesion and biofilm formation. In spite of the enormous abundance of cellulose in plants bacterial celluloses have also been investigated for industrial exploitations read more ...