BACKGROUND AND OBJECTIVES Azotobacter vinelandii, a gamma-proteobacterium, is an obligate aerobic free-living gram-negative soil bacterium capable of fixing nitrogen. Oxygen transfer rate into the cell is reduced by the increase of alginate concentrations during the course of A. vinelandii cultivation. This phenomenon provides a low intracellular oxygen concentration needed for nitrogenase acti...

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...

BACKGROUND AND OBJECTIVES Azotobacter is a diazotroph bacterium reported to possess various plant growth-promoting characteristics.The aim of this study was to isolate Azotobacter strains capable of fixing nitrogen and effectively hydrolyzing both organic and inorganic Pi compounds. MATERIALS AND METHODS In this study, soil samples collected from a diverse range of slightly alkaline soil type...

Azotobacter strains were isolated by serial dilution method and colonies were viscous, smooth, glistening, and brown to black colour on Jenson's N-free agar. Morphological and biochemical tests showed characteristic features of Azotobacter. Further, molecular analyses revealed the presence of different Azotobacter species viz., A. armeniacus, A. chroococcum, A. salinestris, A. tropicalis and A....

The objectives of this study were to count and culture Azotobacter spp. in sampled soils, to determine the nitrogen (N) fixing capacity byAzotobacter spp. in pure culture and different soils, and to explore the relationships between N fixation capacity of Azotobacter spp. and microbiological properties of soils in Northern Anatolia, Turkey. Statistically significant relationships were found bet...

L6hnis and Smith (1923) pointed out that not less than seven different morphological types can be developed and stabilized from Azotobacter cultures. This extreme transmutation of cells has been questioned by subsequent investigators (Lewis, 1937, 1941). Nevertheless, peculiar morphological phases do occur in Azotobacter cultures and no satisfactory explanation has been given as to their functi...

Since the epoch making discoveries of Hellriegel~ there have followed in quick succession many series of investigations relative to the hxation of atmospheric nitrogen by living organisms. Especially brilliant are the investigations of Winogradskyt on Clostridium pastorianum and those of Beyerincka on the Azotobacter group, and it is unnecessary here to go into a review of the investigations wh...

Four laboratory strains and two isolates of Azotobacter vinelandii were found to contain plasmids. Twenty-five laboratory strains which could fix nitrogen did not have free, covalently closed circular plasmid DNA. The plasmids varied in size from 9 to 52 megadaltons, and each strain yielded only one plasmid. No discernible differences in ability to fix nitrogen were found between plasmid-bearin...

As a staple in Indonesian diet, rice demand increase along with the population growth. Therefore, order to fulfill continuous increase, researches were conducted land productivity. The of growth and productivity upland application Azospirillum sp. Azotobacter compost, Azolla, bran carrier studied. Nitrogen fixer applied as biofertiliser mean supply available nitrogen for This research was Cipar...