Acetylation of seaweed alginate by Pseudomonas syringae

Acetylation of bacterial alginate by Pseudomonas syringae subsp. phaseolicola ATCC 19304 was independent of alginate biosynthesis. This allowed the development of a process for acetylating seaweed alginate using immobilized P. syringae ATCC 19304 cells. About 50% of the mannuronic acid residues of seaweed alginate were acetylated by carbon immobilized P. syringae cells in a fluidized bed, up-flow reactor system fed continuously with seaweed alginate and gluconic acid. O-Acetylation by this process was found to be specific for the C-2 and/or C-3 position(s) of mannuronate residues. Acetylated seaweed alginate showed altered properties including increased viscosity and changed affinities for some cations.