Composition of alginate synthesized during the growth cycle of Pseudomonas aeruginosa

A mucoid P. aeruginosa isolated from the sputum of a cystic fibrosis patient was grown in batch culture on a complex medium. During the growth cycle the amount of alginate produced was estimated and its composition was determined by proton magnetic resonance (1H-n.m.r) spectroscopy. Exopolysaccharide production occurred mainly during the exponential phase of growth. The alginate samples isolated varied little in composition and were characterized by being highly acetylated, high mannuronate (0.83-0.93 mole fraction) polymers. Guluronate was present only within heteropolymeric regions of the polysaccharides which all displayed a complete absence of polyguluronate. Ca2+ ion supplementation of the medium was not observed to increase the levels of guluronate in the alginates produced.