Acetobacter xylinum — Biotechnology and Food Technology

Abstract

lntroduction PROTOCOL Biotechnology Acetobacter xylinum is a Gram negative soil bacterium that synthesizes and secretes cellulose as part of its metabolism of glucose. Cellulose is the most abundant natural polymer on Earth, and is the major constituent of the cell wall of plants. The cellulose produced by A. xylinum is structurally and chemically identical to cellulose found in higher plants, and in addition , is not contaminated by lignins or other cellulosic derivatives. It is for this reason that Acetobacter xylinum serves as a potential model organism for the study of cellulose biosynthesis. Cellulose from Acetobacter has potential commercial applications in a variety of industries. The fibrils of cellulose that are synthesized are much narrower than wood fibers, on the order of 0.1 11m, which makes bacterial cellulose a possible material for high quality paper, an emulsifier for paints, and a food additive. Bacterial cellulose has also been used as a skin substitute to protect burned skin, and for ultra filtration technology. Acetobacter xylinum synthesizes cellulose from glucose through a number of enzymatically catalyzed reactions. Glucose is converted into glucose-6-phosphate by Glucokinase. Glucose-6-phosphate is then converted into glucose-1-phosphate by Phosphoglucomutase. Glucose-I-phosphate is then converted into UDP-glucose by UDP-glucose pyrophosphorylase, and finally UDP-glucose is converted to cellulose by Cellulose synthase. Cellulose is considered a secondary metabolite, which