In crude cell-free extracts of Azotobacter chroococcum, nitrogenase was much less sensitive to irreversible inactivation by O2 than was the purified enzyme. When nitrogenase was partially purified by anaerobic discontinuous sucrose-density-gradient centrifugation, O2-tolerance was retained. This preparation was considerably enriched in four polypeptides, three of which were derived from the Mo-...

We describe the production of large amounts of homoand copolymers of polyhydroxyalkanoates (PHAs) by Azotobacter chroococcum strain H23 when growing in culture media amended with alpechin. A. chroococcum grown on NH4+-medium supplemented with alpechin formed PHAs up to 50% of the cell dry weight after 24h. The results show that alpechin supports the growth of strain H23 and also that this waste...

nitrogen and phosphorus are two necessary macronutrients for plant growth and yield. these two elements now will be added to soil by chemical fertilizers. this research has been carried out based on randomized completely block design with three replications at markazi provience agricultural research station, iran, during growing season of 2004-2005 to evaluate the effects of azotobacter chrooco...

Alfred Koch has given considerable attention to the subject of nitrogen fixation by bacteria as resulting from their symbiosis with alga~. Many others have also investigated various features of this problem. In spite of all this there are numerous questions which remain unsolved. The use of soil cultures for such studies is objectionable on account of the soil's complexity, its variety of flora...

A mixture of five saturated 5-n-alkylresorcinol homologues was isolated from vegetative cells of the nitrogen-fixing soil bacterium Azotobacter chroococcum Az12. Their structures were established by spectrometry (1H NMR, EI-MS, FAB-MS, FAB-MS/MS) and chromatography (GC, TLC) means.

The study of the metabolism of Azotobacter has been generally approached from the standpoint of the r6le of this organism in the nitrogen cycle in Nature, but the fact that the ability to fix free nitrogen is regulated by the presence or absence of combined nitrogen in the medium has not been given serious attention although it is made plain in the works to be cited. Bejierink and Van Delden (1...