1887

Abstract

Alginate production by the highly alginate-producing 8821M was maximal at a dissolved oxygen tension (DOT) of 5% of air saturation. Lower DOT limited growth and alginate synthesis. At higher DOT values up to 70% of air saturation, the specific alginate production rate decreased. Nevertheless, the molecular mass of the alginate increased at higher aerations, as indicated by the viscosity of solutions of the isolated biopolymer. The specific activity of the four enzymes leading to GDP-mannuronic acid formation, phosphomannose isomerase (PMI), phosphomannomutase (PMM), GDP-mannose pyrophosphorylase (GMP) and GDP-mannose dehydrogenase (GMD), increased with DOT of up to 25%. At higher DOT, however, only GMP and GMD maintained their maximum values. Changes observed at high oxygen concentrations in the relative activities of PMI and GMP, which are activities of the same bifunctional protein, were attributed to the much higher sensitivity of PMI activity to irreversible oxidative inactivation. The less pronounced decrease of PMM activity at high DOT correlated with an intermediate sensitivity to oxidative inactivation, but could also be related to sequential induction of PMM by the product of the PMI reaction. Thus, oxygen-dependence of alginate synthesis was at least partially the effect of DOT on GDP-mannuronic acid formation. Optimal aerations for maximal alginate production (DOT = 5–10%) were below the aeration level (70%) that led to the highest viscosity. These results suggest that, like GMD, polymerization activity is not very sensitive to oxidative inactivation and they are consistent with the hypothesis that polymerization is dependent on GMD activity, or is regulated in a similar way.

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/content/journal/micro/10.1099/00221287-139-3-441
1993-03-01
2024-03-28
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References

  1. Alves M. J., Martins L. O., Sá-Correia I. 1991; Temperature profiles and alginate synthesis in mucoid and non-mucoid variants of Pseudomonas aeruginosa. Letters in Applied Microbiology 12:244–248
    [Google Scholar]
  2. Bayer A. S., Eftekar F., Tu J., Nast C. C., Speert D. P. 1990; Oxygen up-regulation of mucoid exopolysaccharide (alginate) production in Pseudomonas aeruginosa. Infection and Immunity 58:1344–1349
    [Google Scholar]
  3. Deretic V., Gill J. F., Chakrabarty A. M. 1987; Gene algD coding for GDP-mannose dehydrogenase is transcriptionally activated in mucoid Pseudomonas aeruginosa. Journal of Bacteriology 169:351–358
    [Google Scholar]
  4. Deretic V., Govan J. R. W., Koniecsni W. M., Martin D. W. 1990; Mucoid Pseudomonas aeruginosa in cystic fibrosis: mutations in the muc loci affect transcription of the algR and algD genes in response to environmental stimuli. Molecular Microbiology 4:189–196
    [Google Scholar]
  5. Deretic V., Mohr C. D., Martin D. W. 1991; Mucoid Pseudomonas aeruginosa in cystic fibrosis: signal transduction and histone-like elements in the regulation of bacterial virulence. Molecular Microbiology 5:1577–1583
    [Google Scholar]
  6. DeVault J. D., Berry A., Misra T. K., Darzins A., Chakrabarty A. M. 1989; Environmental sensory signals and microbial pathogenesis: Pseudomonas aeruginosa in cystic fibrosis. Bio/Technology 7:352–357
    [Google Scholar]
  7. DeVault J. D., Hendrickson W., Kato J., Chakrabarty A. M. 1991; Environmentally regulated >algD promoter is responsive to the cAMP receptor protein in Escherichia coli. Molecular Microbiology 5:2503–2509
    [Google Scholar]
  8. Estell D. A., Graycar T. P., Wells J. A. 1985; Engineering an enzyme by site-directed mutagenesis to be resistant to chemical oxidation. Journal of Biological Chemistry 260:6518–6521
    [Google Scholar]
  9. Knutson C. A., Jeanes A. 1968; A new modification of the carbazole analysis: application to heteropolysaccharides. Analytical Biochemistry 24:470–481
    [Google Scholar]
  10. Leitão J. H., Fialho A. M., Sá-Correia I. 1992; Effects of growth temperature on alginate synthesis and enzymes in Pseudomonas aeruginosa variants. Journal of General Microbiology 138:605–610
    [Google Scholar]
  11. Martins L. O., Brito L. C., Sá-Correia I. 1990; Roles of Mn2+, Mg2+ and Ca2+ on alginate biosynthesis by Pseudomonas aeruginosa. Enzyme and Microbial Technology 12:794–799
    [Google Scholar]
  12. Nosoh Y., Sekiguchi T. 1991 Protein Stability and Stabilization through Protein Engineering New York: Ellis Horwood.;
    [Google Scholar]
  13. Sá-Correia I., Darzins A., Wang S. -K., Berry A., Chakra-Barty A. M. 1987; Alginate biosynthetic enzymes in mucoid and nonmucoid Pseudomonas aeruginosa: overproduction of phosphomannose isomerase, phosphomannomutase and GDP-mannose pyrophosphorylase by overexpression of phosphomannose isomerase (pmi). gene Journal of Bacteriology 169:3224–3231
    [Google Scholar]
  14. Shinabarger D., Berry A., May T. B., Rothmel R., Fialho A. M., Chakrabarty A. M. 1991; Purification and characterization of phosphomannose isomerase-guanosine diphospho-d-mannose pyrophosphorylase. Journal of Biological Chemistry 266:2080–2088
    [Google Scholar]
  15. Sutherland I. W. 1990 Biotechnology of Microbial Exopolysaccharides Cambridge: Cambridge University Press.;
    [Google Scholar]
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