• We are sorry, but NCBI web applications do not support your browser and may not function properly. More information
Logo of aemPermissionsJournals.ASM.orgJournalAEM ArticleJournal InfoAuthorsReviewers
Appl Environ Microbiol. Jan 1997; 63(1): 21–26.
PMCID: PMC1389089

Exopolysaccharide and Poly-(beta)-Hydroxybutyrate Coproduction in Two Rhizobium meliloti Strains


The effects of different nitrogen and carbon sources on cell growth, pH, and exopolysaccharide (EPS) and poly-(beta)-hydroxybutyrate (PHB) production by two strains of Rhizobium meliloti (M5N1 and Su47) are reported. Differences in the behavior of glucose- and fructose-grown cells were shown, in particular with the M5N1 strain. Growth in a glucose-containing medium was accompanied by acidification of the culture medium, which leads to cell death. On fructose, acidification was detected only in the medium with a mineral nitrogen supply. A lag phase in EPS production was observed with cells grown with glucose, probably related to an initial extracellular conversion of the carbohydrate into an acid. No lag phase was observed in EPS production from fructose or in PHB synthesis whatever the carbon source. A decrease in PHB content was noticed for both strains under conditions where acidification of media occurred. The extent of production, emphasized by the use of a coproduction index, indicates that the M5N1 strain is a more promising organism than is the Su47 strain for polymer production. Such a strain, put in rich medium (containing yeast extract) supplemented with fructose, accumulated PHB up to 85% of dry cell weight and excreted about 1.5 g of EPS per liter in the medium. Regulation of the coproduction of EPS and PHB by these cells is suggested.

Full Text

The Full Text of this article is available as a PDF (218K).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • Anderson AJ, Dawes EA. Occurrence, metabolism, metabolic role, and industrial uses of bacterial polyhydroxyalkanoates. Microbiol Rev. 1990 Dec;54(4):450–472. [PMC free article] [PubMed]
  • Breedveld MW, Miller KJ. Cyclic beta-glucans of members of the family Rhizobiaceae. Microbiol Rev. 1994 Jun;58(2):145–161. [PMC free article] [PubMed]
  • Cornish A, Greenwood JA, Jones CW. Binding-protein-dependent glucose transport by Agrobacterium radiobacter grown in glucose-limited continuous culture. J Gen Microbiol. 1988 Dec;134(12):3099–3110. [PubMed]
  • Encarnación S, Dunn M, Willms K, Mora J. Fermentative and aerobic metabolism in Rhizobium etli. J Bacteriol. 1995 Jun;177(11):3058–3066. [PMC free article] [PubMed]
  • Fidler S, Dennis D. Polyhydroxyalkanoate production in recombinant Escherichia coli. FEMS Microbiol Rev. 1992 Dec;9(2-4):231–235. [PubMed]
  • Gardiol A, Arias A, Cerveñansky C, Gaggero C, Martínez-Drets G. Biochemical characterization of a fructokinase mutant of Rhizobium meliloti. J Bacteriol. 1980 Oct;144(1):12–16. [PMC free article] [PubMed]
  • Jan S, Roblot C, Goethals G, Courtois J, Courtois B, Saucedo JE, Séguin JP, Barbotin JN. Study of parameters affecting poly(3-hydroxybutyrate) quantification by gas chromatography. Anal Biochem. 1995 Mar 1;225(2):258–263. [PubMed]
  • Midgley M, Dawes EA. The regulation of transport of glucose and methyl alpha-glucoside in Pseudomonas aeruginosa. Biochem J. 1973 Feb;132(2):141–154. [PMC free article] [PubMed]
  • O'hara Graham W, Goss Thomas J, Dilworth Michael J, Glenn Andrew R. Maintenance of Intracellular pH and Acid Tolerance in Rhizobium meliloti. Appl Environ Microbiol. 1989 Aug;55(8):1870–1876. [PMC free article] [PubMed]
  • Patel JJ, Gerson T. Formation and utilisation of carbon reserves by Rhizobium. Arch Microbiol. 1974;101(3):211–220. [PubMed]
  • Romanov VI, Hernández-Lucas I, Martínez-Romero E. Carbon Metabolism Enzymes of Rhizobium tropici Cultures and Bacteroids. Appl Environ Microbiol. 1994 Jul;60(7):2339–2342. [PMC free article] [PubMed]
  • Sutherland IW. Biosynthesis and composition of gram-negative bacterial extracellular and wall polysaccharides. Annu Rev Microbiol. 1985;39:243–270. [PubMed]
  • Whiting PH, Midgley M, Dawes EA. The role of glucose limitation in the regulation of the transport of glucose, gluconate and 2-oxogluconate, and of glucose metabolism in Pseudomonas aeruginosa. J Gen Microbiol. 1976 Feb;92(2):304–310. [PubMed]
  • Williams SG, Greenwood JA, Jones CW. Agrobacterium radiobacter and related organisms take up fructose via a binding-protein-dependent active-transport system. Microbiology. 1995 Oct;141(Pt 10):2601–2610. [PubMed]
  • Zevenhuizen LP. Cellular glycogen, beta-1,2,-glucan, poly beta-hydroxybutyric acid and extracellular polysaccharides in fast-growing species of Rhizobium. Antonie Van Leeuwenhoek. 1981;47(6):481–497. [PubMed]

Articles from Applied and Environmental Microbiology are provided here courtesy of American Society for Microbiology (ASM)


Related citations in PubMed

See reviews...See all...

Cited by other articles in PMC

See all...


Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...