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TY - JOUR AU - Post, E. AU - Kleiner, D. AU - Oelze, J. PY - 1983 DA - 1983/01/01 TI - Whole cell respiration and nitrogenase activities in Azotobacter vinelandii growing in oxygen controlled continuous culture JO - Archives of Microbiology SP - 68 EP - 72 VL - 134 IS - 1 AB - 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 (sR) 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 sR. SN - 1432-072X UR - https://doi.org/10.1007/BF00429410 DO - 10.1007/BF00429410 ID - Post1983 ER -