Bacterial Alginate Biosynthesis and Metabolism

Alginate is a linear anionic heteropolysaccharide with chemical structure consisting of 1,4-linked subunits β-D-mannuronic acid (M) and its C-5 epimer α-L-guluronic (G). It well known that the monomer composition molecular weight alginates affect their properties influence use in food pharmaceutical industries. usually extracted from seaweed for commercial purposes, but can also be produced by bacteria as exopolysaccharide (EPS). Pseudomonas spp. Azotobacter vinelandii are well-known alginate-producing microorganisms. Their biochemical machinery alginate biosynthesis influenced changing culture conditions manipulating genes/proteins, making it relatively easy to obtain customized EPS different weights, M/G compositions, thus physicochemical properties. Although these two genera have very similar biosynthetic pathways mechanisms production, most genes involved being virtually identical, regulation has been shown somewhat different. In this chapter, we present main steps bacteria, including precursor synthesis, polymerization, periplasmic modifications, transport/secretion, post-secretion modification.