Investigations with the isotopic tracer N16 have furnished definite evidence that ammonia is the key intermediate in nitrogen fixation by Azotobacter vinelundii (1). Direct isolation of the intermediate, however, has not been possible, apparently because ammonia is used so rapidly by this bacterium that it does not accumulate. In a study of the comparative biochemistry of nitrogen fixation, we ...

An earlier report (1) dealing with the distribution of isotopic nitrogen in cells of Axotobacter vinelandii fixing molecular nitrogen provided evidence that ammonia might be the initial stable form of nitrogen in the fixation process. This conclusion was based on the observation that the N’s supplied this organism accumulated in the glutamic acid fraction, as had been already observed in higher...

Growth and utilization of different phenolic acids present in olive mill wastewater (OMW) by Azotobacter chroococcum were studied in chemically defined media. Growth and utilization of phenolic acids were only detected when the microorganism was cultured on p-hydroxybenzoic acid at concentration from 0.01% to 0.5% (w/v) and protocatechuic acid at concentration from 0.01% to 0.3% (w/v) as sole c...

Biological N2 fixation, the reduction of N2 to NH 3 , is catalyzed by the enzyme nitrogenase . Fractionation studies of nitrogenases from a variety of organisms have shown that all are composed of two similar proteins, one contains Mo and Fe and is called the Mo-Fe protein and the other contains only Fe and is called the Fe protein . Recently homogeneous preparations of these proteins from Azot...

Azotobacter vinelandii ferredoxin I is a small protein that contains one [4Fe-4S] cluster and one [3Fe-4S] cluster. Recently the x-ray crystal structure has been redetermined and the fdxA gene, which encodes the protein, has been cloned and sequenced. Here we report the site-directed mutation of Cys-20, which is a ligand of the [4Fe-4S] cluster in the native protein, to alanine and the characte...

Strains of Azotobacter vinelandii which contain defined deletions within the nifD and nifK genes which encode, respectively, the alpha and beta subunits of the MoFe protein of nitrogenase were analyzed. When synthesized without its partner, the beta subunit accumulated as a soluble beta 4 tetramer. In contrast, when the alpha subunit was present without its partner, it accumulated primarily as ...

The aim of this research was to investigate the effect of inoculation (Azotobacter chroococcum and actinomycetes) and nitrogen mineral fertilizers (doses of 60 kg N ha-1 and 120 kg N ha-1) on the yield of wheat and on the number and activity of certain microorganisms in rhizospheric soil. The investigation was carried out in humogley soil with three wheat varieties. The variants of the experime...

Azotobacter vinelandii contains a heterodimeric, membrane-bound [NiFelhydrogenase capable of catalyzing the reversible oxidation of H2. The 13 and at subunits of the enzyme are encoded by the structural genes hoxK and hoxG, respectively, which appear to form part of an operon that contains at least one further potential gene (open reading frame 3 1ORF3]). In this study, determination of the nuc...

In this study, aimed to investigate the effect of bacterial fertilizer: A (Bacillus spp., Trichoderma spp. ), B (Azorhizobium, Azotobacter and Azospirillum) C (Azotobacter Bacillus Pseudomonas putida) on soil carbon mineralization. On application A, fertilizers sterilized control soil, whose initial mineralization rates is 1.1%, 5.12%, 3.54%, 10.78% were respectively recorded. According these r...

A field experiment was conducted at the experimental site of Department Soil Science and Water Management, College Horticulture Forestry, Neri, Hamirpur (Himachal Pradesh). The consisted eleven treatments which were carried out in randomized block design with three replications. Observations for micronutrient uptake soil physical properties recorded it found that lowest bulk density achieved tr...