STUDIES OF AEROBIC NON-SYMBIOTIC NITROGEN-FIXING BACTERIA

1961 ◽  
Vol 7 (1) ◽  
pp. 7-13 ◽  
Author(s):  
E. A. Paul ◽  
J. D. Newton
Keyword(s):  
Azotobacter Chroococcum ◽  
Nitrogen Fixing ◽  
Nitrogen Fixing Bacteria ◽  
Canadian Prairie ◽  
Gram Negative ◽  
Mannitol Solution ◽  
Litmus Milk ◽  
Glucose Agar ◽  
Solution Cultures ◽  
Prairie Province

The occurrence of aerobic, non-symbiotic, nitrogen-fixing bacteria was determined in samples of soil collected in the various soil zones of Alberta and Saskatchewan. Mannitol and sodium benzoate dust-plates, and mannitol solution cultures with subsequent inoculation onto mannitol agar demonstrated that Azotobacter were not widespread in the Canadian prairie province soils. These procedures also led to the isolation of smaller, aerobic, non-symbiotic, nitrogen-fixing organisms from all the Alberta and Saskatchewan soils studied. These smaller, nitrogen-fixing bacteria which developed as 1- to 3-mm circular, convex, unpigmented colonies on mannitol and glucose agar were classified as Pseudomonas. Flagellation of the 0.75 to 1 μ by 1.5- to 2-μ Gram-negative, coccoid rods was polar. Starch was hydrolyzed; gelatin was not liquified. Indol, acid, and gas were not produced; litmus milk was not reduced, but hydrogen sulphide was formed. The pseudomonads, capable of initiating growth at a pH of 4.9, could also grow at 8 °C, whereas the Azotobacter chroococcum required higher temperatures and reactions above pH 6.2. Azotobacter chroococcum fixed up to 12 mg nitrogen per gram of carbohydrate. The smaller bacteria, classified as Pseudomonas azotogensis, fixed from 0.1 to 3.9 mg N per gram of mannitol.

A MICROBIOLOGICAL STUDY OF PODSOL SOIL PROFILES: III. BACTERIA FOUND IN SEPARATE HORIZONS

1935 ◽  
Vol 13c (4) ◽  
pp. 256-262 ◽  
Author(s):  
P. H. H. Gray
Keyword(s):  
Systematic Position ◽  
Soil Profiles ◽  
Nitrogen Fixing ◽  
Biochemical Reactions ◽  
Nitrogen Fixing Bacteria ◽  
Gram Negative ◽  
Microbiological Study ◽  
Anaerobic Organism ◽  
Aerobic Organism

An investigation has been made to determine the presence of bacteria concerned in certain important biochemical reactions in the separate horizons of five heavily leached (podsol) soils of Quebec. Cellulose decomposing bacteria were represented by a species of Micrococcus, and by Cytophaga hutchinsoni. Organisms of the group Mycobacteriaceae were found in mediums devised to isolate bacteria able to decompose phenol and naphthalene. Of the nitrogen-fixing bacteria the aerobic organism Azotobacter was absent, but the anaerobic organism, Bacillus amylobacter, was present in all of the horizons. The decomposition of urea was due to Gram-negative spore-forming rods whose systematic position has not been determined.

scholarly journals The kinetics of the reduction of isocyanides, acetylenes and the cyanide ion by nitrogenase preparation from Azotobacter chroococcum and the effects of inhibitors

1968 ◽  
Vol 107 (1) ◽  
pp. 1-6 ◽  
Author(s):  
M Kelly
Keyword(s):  
Carbon Monoxide ◽  
Nitrogen Fixation ◽  
Azotobacter Chroococcum ◽  
Nitrogen Fixing ◽  
Cyanide Ion ◽  
Nitrogen Fixing Bacteria ◽  
Methyl Isocyanide ◽  
Kinetics Of

1. Nitrogen-fixing preparations from Azotobacter chroococcum reduced substrates with the following Km values: methyl isocyanide, 1·8×10−4m; ethyl isocyanide, 2·5×10−2m; cyanide ion, 1·4×10−3m; acetylene, 1·2×10−4m. 2. Nitrogen, carbon monoxide or hydrogen competitively inhibited isocyanide reduction with the following Ki values: hydrogen, 1·3×10−3m; carbon monoxide, 6·8×10−6m; nitrogen, 4·3×10−4m. 3. Living nitrogen-fixing bacteria, and isolated clover nodules, formed methane from methyl isocyanide. 4. These results are discussed in relation to other work and possible mechanisms of nitrogen fixation.

Distribution of Azotobacter in Eastern Canadian soils and in association with plant rhizospheres

1988 ◽  
Vol 34 (6) ◽  
pp. 815-817 ◽  
Author(s):  
Manoj M. Kole ◽  
William J. Page ◽  
Illimar Altosaar
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Ph ◽  
Soil Type ◽  
Soil Moisture Content ◽  
Azotobacter Chroococcum ◽  
Nitrogen Fixing ◽  
Nitrogen Fixing Bacteria ◽  
Canadian Soils

Aerobic nitrogen-fixing bacteria were readily isolated from Eastern Canadian soils. The majority (89%) of these soils were found to contain Azotobacter chroococcum and other members of this family. These bacteria ranged from 1 × 102 to 2.5 × 104 bacteria per gram soil. The soil type had relatively little effect on the population of these bacteria provided a soil moisture content of 10 to 18% and a soil pH of 6.5 to 8.0 was maintained. The presence of wheat or common lawn grasses did not promote better establishment of Azotobacteraceae. However, slightly larger populations of these bacteria were associated with corn, oat, and soybean rhizospheres.

scholarly journals Cowpea symbiotic efficiency, pH and aluminum tolerance in nitrogen-fixing bacteria

2014 ◽  
Vol 71 (3) ◽  
pp. 171-180 ◽  
Author(s):  
Bruno Lima Soares ◽  
Paulo Avelar Ademar Ferreira ◽  
Silvia Maria de Oliveira-Longatti ◽  
Leandro Marciano Marra ◽  
Marcia Rufini ◽  
...  
Keyword(s):  
Aluminum Tolerance ◽  
Nitrogen Fixing ◽  
Nitrogen Fixing Bacteria ◽  
Symbiotic Efficiency
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