Bacteria Cellulose

Cellulose is biopolymer on earth, recognized as the major component of plant biomass, but also a representative of microbial extracellular polymers. Bacterial cellulose (BC) belongs to specific products of primary metabolisms and is mainly a protective coating, whereas plant cellulose (PC) plays a structural role.

Cellulose is synthesized by bacteria belonging to the genera acetobacter, rhizobium, Agrobacterium, and Sarcina. Its most efficient producers are gram-negative, acetic acid bacteria Acetobacter xylinum, which have been applied as model microorganisms for basic and applied studies on cellulose. Investigations have been focused on the mechanism of biopolymer synthesis, as well as on its structure and properties, which determine practical use. One of the most important features of BC is its chemical purity, which distinguishes this cellulose from that from plants, usually associated with hemicelluloses and lignin, removal of which is inherently difficult.

Because of the unique properties, resulting from the ultrafine reticulated structure, BC has found a multitude of applications in paper, textile, and food industries, and as a biomaterial in cosmetics and medicine. Wider application of this polysaccharide is obviously dependent on the scale of production and its cost. Therefore, basic studies run together with intensive research on strain improvement and production process development.

Cellulose is an unbranched polymer of β-1,4-linked glucopyranose residues. Extensive research on BC revealed that it is chemically identical to PC, but its macromelecular structure and properties differ from the latter. Nascent chains of BC aggregate to form subfibrils, which have a width of approximately 1.5 nm and belong to the thinnest naturally occurring fibers, comparable only to subelemental fibers, comparable only to subelemental fibers of cellulose detected in the cambium of some plants and in quinee mucous. Dimensions of the ribbons are 3 – 4 (thickness) x 70 – 80 nm (width), according to Zarr (1977), 3.2 x 133 nm, according to Brown et al. (1976).