Advertisement

Immobilization of Zymomonas mobilis 2716, for the protection of cellular activity

  • L. A. Kirk
  • H. W. Doelle
  • R. I. Webb
Research Paper

Abstract

Alginate-immobilized Zymomonas mobilis cells produced 17.8% (v/v) ethanol in less than 24 h, with an ethanol yield of 97%, compared with 88% for free cells, using a fed-batch cultivation technique. The substrate, glucose, was added intermittently in powder form to foster nucleation of the CO2 formed. Repeated-batch cultivation led to complete utilization of approximately 200 g glucose/l in 7.5 h with a 98% conversion efficiency to ethanol. Free cells used the glucose less efficiently (conversion efficiency of 78%), and even after 100 h the glucose was not fully consumed. Freeze-substitution electron microscopy studies showed that immobilized cells generally displayed lesser blebbing and membrane disruption than free cells. These studies further suggest that membrane blebbing may be due to an effect of high initial glucose levels, and not due to the accumulation of end-products ethanol and CO2.

Key words

Alginate freeze-substitution immobilization Zymomonas mobilis 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Burrill, H., Doelle, H.W. & Greenfield, P.F. 1983 The inhibitory effect of ethanol producton by Zymomonas mobilis. Biotechnology Letters 5, 423–428.Google Scholar
  2. Doelle, M.B. & Doelle, H.W. 1989 Ethanol production from sugar cane syrup using Zymomonas mobilis. Journal of Biotechnology 11, 25–36.CrossRefGoogle Scholar
  3. Doelle, H.W. & McGregor, A.N. 1983 The effect of high ethanol and CO2 concentrations on the ultrastructure of Zymomonas mobilis. European Journal of Applied Microbiology and Biotechnology 17, 44–48.Google Scholar
  4. Doelle, H.W., Preusser, H.J. & Rostek, H. 1982 Electron microscopic investigations of Zymomonas mobilis cells grown in low and high glucose concentrations. European Journal of Applied Microbiology and Biotechnology 16, 136–141.Google Scholar
  5. Graham, L.L. & Beveridge, T.J. 1990a Evaluation of freeze-substitution and conventional embedding protocols for routine electron microscopic processing of Eubacteria. Journal of Bacteriology 172, 2141–2149.PubMedGoogle Scholar
  6. Graham, L.L. & Beveridge, T.J. 1990b Effect of chemical fixatives on accurate preservation of Escherichia coli and Bacillus subtilis structure in cells prepared by freeze-substitution. Journal of Bacteriology 172, 2150–2159.PubMedGoogle Scholar
  7. Graham, L.L., Harris, R., Villiger, W. & Beveridge, T.J. 1991 Freeze-substitution of Gram-negative Eubacteria: general cell morphology and envelope profiles. Journal of Bacteriology 173, 1623–1633.PubMedGoogle Scholar
  8. Hobot, J.A., Carlemalm, E., Villiger, W. & Kellenberger, E. 1984 Periplasmic gel: new concept resulting from the reinvestigation of bacterial cell envelope ultrastructure by new methods. Journal of Bacteriology 160, 143–152.PubMedGoogle Scholar
  9. Holcberg, I.B. & Margalith, P. 1981 Alcoholic fermentation by immobilized yeast at high sugar concentrations. European Journal of Applied Microbiology and Biotechnology 13, 133–140.Google Scholar
  10. Ingram, L.O. 1990 Ethanol tolerance in bacteria. Critical Reviews in Biotechnology 9, 305–319.PubMedGoogle Scholar
  11. King, F.G. & Hossain, M.A. 1982 The effect of temperature, pH, and initial glucose concentration on the kinetics of ethanol production by Zymomonas mobilis in batch fermentation. Biotechnology Letters 4, 531–536.Google Scholar
  12. Kirk, L.A. & Doelle, H.W. 1992 The effects of potassium and chloride ions on the ethanolic fermentation of sucrose by Zymomonas mobilis 2716. Journal of Applied Microbiology and Biotechnology 37, 88–93.Google Scholar
  13. Laudrin-Seiller, I., Torrijos, M., Uribelarrea, J.L. & Goma, G. 1984 Alcoholic fermentation by Zymomonas mobilis: effect of initial substrate on physiological parameters. Biotechnology Letters 6, 477–480.Google Scholar
  14. Lin, J.J., Dale, M.C. & Okos, M.R. 1991 Osmotic (a W) effects on growth and ethanol production of free and immobilized Zymomonas mobilis. Process Biochemistry 26, 143–151.CrossRefGoogle Scholar
  15. Martinsen, A., Storrø, I. & Skjåk-Bræk, G. 1992 Alginate as immobilization material: III Diffusional properties. Biotechnology and Bioengineering 39, 186–194.Google Scholar
  16. Parry, R.W., Dietz, P.M., Tellefsen, R.L. & Steiner, L.E. (eds) 1975 Chemistry: Experimental Foundations, 2nd edn. p. 577. Englewood Cliffs, New Jersey: Prentice-Hall.Google Scholar
  17. Reynold, E.S. 1963 The use of lead citrate at high pH as an electron opaque stain in electron microscopy. Journal of Cellular Biology 17, 208–212.Google Scholar
  18. Rogers, P.L., Lee, K.J. & Tribe, D.E. 1979 Kinetics of alcohol production by Zymomonas mobilis at high sugar concentrations. Biotechnology Letters 1, 165–170.Google Scholar
  19. Struch, T., Neuss, B., Bringer-Meyer, S. & Sahm, H. 1991 Osmotic adjustment of Zymomonas mobilis to concentrated glucose solutions. Applied Microbiology and Biotechnology 34, 518–523.Google Scholar
  20. Veeramallu, U.K. & Agrawal, P. 1986 The effect of CO2 ventilation on kinetics and yields of cell mass and ethanol in batch cultures of Zymomonas mobilis. Biotechnology Letters 8, 811–816.Google Scholar
  21. Weir, P.M. & Chase, T. 1991 Inhibition of Zymomonas growth by carbon sources. Biotechnology Letters 13, 779–780.Google Scholar

Copyright information

© Rapid Communications of Oxford Ltd 1993

Authors and Affiliations

  • L. A. Kirk
  • H. W. Doelle
  • R. I. Webb

There are no affiliations available

Personalised recommendations