It is described biologically pure bacterial cultures of mutant strains of
Pseudomonas fluorescens, which produces large amounts of alginate. The
alginate may contain a certain determined content of mannuronate and
guluronate residues, possible presence and determined level of acetyl
groups in the alginate, and a desired molecular weight of the alginate.
Also high yielding mutants with regulation of alginate production, is
described. The invention further provides methods for producing new
mutant strains of Pseudomonas fluorescens and variants thereof, and use
the resulting strains in alginate production.