Isolation of alginate-producing mutants of Pseudomonas fluorescens, Pseudomonas putida and Pseudomonas mendocina

Area of Science:

• Microbiology
• Bacterial Genetics
• Biochemistry

Background:

• Alginate production is a key characteristic in certain bacterial species, influencing biofilm formation and virulence.
• Pseudomonas species are known for their diverse metabolic capabilities and ecological roles.
• Mucoid variants, often associated with alginate overproduction, are significant in clinical and environmental contexts.

Purpose of the Study:

• To investigate the spontaneous occurrence of alginate-producing (muc) variants in various Pseudomonas species.
• To characterize the exopolysaccharide produced by these variants using spectroscopic methods.
• To determine the prevalence of muc variants across a range of Pseudomonas species.

Main Methods:

• Isolation of spontaneous mucoid variants from selected Pseudomonas strains.
• Selection of variants based on carbenicillin resistance.
• Infrared (IR) spectroscopy analysis of the bacterial exopolysaccharide.

Main Results:

• Spontaneous alginate-producing (muc) variants were isolated from Pseudomonas fluorescens, P. putida, and P. mendocina at a frequency of 10^-8.
• Infrared spectrum analysis confirmed the exopolysaccharide as an acetylated alginate.
• Mucoid variants were not found in P. stutzeri, P. pseudoalcaligenes, P. testosteroni, P. diminuta, P. acidovorans, P. cepacia, or P. maltophilia.

Conclusions:

• Certain Pseudomonas species, including P. fluorescens, P. putida, and P. mendocina, can spontaneously generate alginate-producing variants.
• The identified exopolysaccharide is structurally similar to alginates found in Azotobacter vinelandii and mucoid Pseudomonas aeruginosa.
• The capacity for spontaneous alginate production varies significantly among different Pseudomonas species.