Abstract
Azotobacter vinelandii strain OP was grown in continuous culture at various dissolved oxygen concentrations of air (100% air saturation of the medium=225 ±14 μM O2). Sucrose was added as carbon source and either dinitrogen or ammonia as nitrogen sources. Irrespective of the nitrogen source steady state cultures showed the following general responses with dissolved oxygen concentrations increasing from about 1% to 30% air saturation: (i) cell protein levels, (ii) the amount of cell protein formed per sucrose consumed as well as (iii) nitrogenase activity decreased by at least a factor of two while (iv) cellular respiration increased. At higher oxygen concentrations the parameters changed only slightly, if at all. Increasing the sucrose concentration in the inflowing medium (s R) from 3 g/l to 15 g/l increased the total level of cellular respiration with nitrogen-fixing cultures but was more pronounced with ammonium-assimilating cultures. With nitrogen-fixing cultures cell protein levels increased five-fold while the ratio of protein formed per sucrose consumed as well as cellular nitrogenase activity remained unaffected. With ammonium-assimilating cultures the cell protein level was only doubled and the level of cell protein formed per sucrose consumed was decreased at the higher s R.
Increasing the dilution rate at a constant oxygen concentration of 45% air saturation resulted in an almost parallel increase of both cellular respiratory and nitrogenase activity at low and moderate dilution rates. At high dilution rates nitrogenase activity increased steeply over the respiratory activity. Nitrogen-fixing cultures adapted to various oxygen concentrations were subjected to oxygen stress by increasing the oxygen concentration for 7 min. In all cases, this resulted in a complete inhibition (‘switch-off’) of nitrogenase activity. Upon restoration of the original oxygen concentration nitrogenase activity returned to a decreased level. The discussion arrives at the conclusion that some of the results are incompatible with the concept of respiratory protection of nitrogenase.
Similar content being viewed by others
References
Ackrell BAC, Jones CW (1971) The respiratory system of Azotobacter vinelandii. 2. Oxygen effects. Eur J Biochem 20:29–35
Dalton H, Postgate JR (1969a) Effect of oxygen on growth of Azotobacter chroococcum in batch and continuous cultures. J Gen Microbiol 54:463–473
Dalton H, Postgate JR (1969b) Growth and physiology of Azotobacter chroococcum in continuous culture. J Gen Microbiol 56:307–319
Haaker H, Veeger C (1977) Involvement of the cytoplasmic membrane in nitrogen fixation by Azotobacter vinelandii. Eur J Biochem 77:1–10
Hill S, Drozd JW, Postgate JR (1972) Environmental effects on the growth of nitrogen-fixing bacteria. J Appl Chem Biotechnol 22: 541–558
Jones CW, Brice JM, Wright V, Ackrell BAC (1973) Respiratory protection of nitrogenase in Azotobacter vinelandii. FEBS Lett 29:77–81
Lowry OH, Rosebrough NJ, Farr AL, Randall RJ (1951) Protein measurement with the Folin phenol reagent. J Biol Chem 193:265–275
Oppenheim J, Fisher RJ, Wilson PW, Marcus L (1970) Properties of a soluble nitrogenase in Azotobacter. J Bacteriol 101:292–296
Phillips DA, Johnson MJ (1961) Aeration in fermentations. J Biochem Microbiol Technol Eng 3:277–309
Post E, Golecki JR, Oelze J (1982) Morphological and ultrastructural variations in Azotobacter vinelandii growing in oxygen-controlled continuous culture. Arch Microbiol 133:75–82
Postgate JR (1974) Prerequisites for biological nitrogen fixation in freeliving heterotrophic bacteria. In: Quispel A (ed) The biology of nitrogen fixation. Elsevier, Amsterdam, pp 663–686
Robson RL (1979) Characterization of an oxygen-stable nitogenase complex isolated from Azotobacter chroococcum. Biochem J 181: 569–575
Robson RL, Postgate JR (1980) Oxygen and hydrogen in biological nitrogen fixation. Ann Rev Microbiol 34:183–207
Veeger C, Laane C, Scherings G, Matz L, Haaker H, Van Zeeland-Wolbers L (1980) Membrane energization and nitrogen fixation in Azotobacter vinelandii and Rhizobium leguminosarum. In: Newton WE, Orme-Johnson WH (eds) Nitrogen fixation, vol 1. University Park Press, Baltimore, pp 111–137
Wyss O, Neumann MG, Socolofsky MD (1961) Development and germination of the Azotobacter cyst. J Biophys Biochem Cytol 10:555–565
Yates MG, Jones CW (1974) Respiration and nitrogen fixation in Azotobacter. Adv Microb Physiol 11:97–135
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Post, E., Kleiner, D. & Oelze, J. Whole cell respiration and nitrogenase activities in Azotobacter vinelandii growing in oxygen controlled continuous culture. Arch. Microbiol. 134, 68–72 (1983). https://doi.org/10.1007/BF00429410
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00429410