Isolation of Alginate-producing Mutants of Pseudomonas fluorescens, Pseudomonas putida and Pseudomonas mendocina

1 Department of Bacteriology, University of Edinburgh, Medical School, Teviot Place, Edinburgh EH8 9AG, U.K. 2 Tate and Lyle Ltd, Group Research and Development, P.O. Box 68, Reading RG6 2BX, U.K. ABSTRACT Spontaneous alginate-producing ( muc ) variants were isolated from strain of Pseudomonas fluorescens, P. putida and P. mendocina at a frequency of 1 in 10 8 by selcting for carbenicillin resistance. The infrared spectrum of the bacterial exopolysaccharide was typical of an acetylated alginate similar to that previously described in Azotobacter vinelandil and in mucoid variants of P. aeruginosa . Mucoid variants were not isolated from P. stuteri, P. pseudoalcaligenes, P. testosteroni, P. diminuta, P. acidovorans, P. cepacia or P. maltophilia .