ISSN:
1476-5535
Keywords:
Keywords: Sphingomonas; exopolysaccharide; productivity; biosynthetic-gene augmentation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
Certain bacteria of the Sphingomonas genus secrete structurally related capsular polysaccharides. Due to their unique properties, three (gellan, welan and rhamsan) are produced commercially by submerged fermentation and are used as modifiers of aqueous rheology and as gelling agents. However, conversion of glucose into these polysaccharides is relatively inefficient. To identify general methods for increasing the productivity of Sphingomonas, we augmented the normal chromosomal copy of the phosphoglucomutase gene (pgm) and the cluster of genes (sps) required for assembly of the carbohydrate repeat unit for strain S7 with multiple copies of plasmids carrying these genes. Although a sixfold increase in Pgm activity only lead to a small percentage increase in conversion of glucose to the S-7 polysaccharide, multiple sps genes caused a nearly 20% increase in the yield from glucose and an even larger increase in culture viscosity. The increased viscosity was accompanied by a change in the sugar composition of the secreted polymer. Journal of Industrial Microbiology & Biotechnology (2000) 25, 49–57.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1038/sj.jim.7000019
Permalink
