ALGINATE FROM PSEUDOMONAS-FLUORESCENS AND P-PUTIDA - PRODUCTION AND PROPERTIES

The alginate-like polysaccharides synthesized by Pseudomonas fluoresce ns and Pseudomonas putida have been prepared from batch cultures grown with glucose and fructose as carbon substrates. Despite the different methods of catabolism of the two substrates and synthesis of the algi nate precursors, both strains produced polysaccharides which were cons istent in their composition of mannuronic and guluronic acids and in t he frequency of occurrence of dimers of D-mannuronic acid. All prepara tions lacked homooligomeric sequences of L-guluronic acid and were hig hly acetylated (12-21%). In all the culture conditions tested, polysac charide production was growth-associated and maximum M(r) was obtained after 48 h growth; older cultures contained material of progressively lower M(r). This was ascribed to the degradative activity of alginate lyases which were detected intracellularly in both species and are pr esumably released by cell lysis. At 72 h, alginate from P. putida grow n on either substrate had an M(r) of only 34000-38500, whereas the pro duct from P. fluorescens grown on fructose had an M(r) of 300000 and t hat from glucose-grown cultures an M(r) of 72000.