This paper deals with adsorption of Pb and Hg on the exopolysaccharide produced by Azotobacter chroococcum XU1. The adsorption of metal ions was significantly affected by the pH of metal solutions (Pb(NO3)2 and Hg(NO3)2), metal ions concentration and exopolysaccharide concentrations. At optimum pH the uptakes of the metals were 40.48% and 47.87% respectively. The metal ions biosorption was high...

In addition to their g = 1.94 EPR signal, nitrogenase Fe-proteins from Azotobacter vinelandii, Azotobacter chroococcum and Klebsiella pneumoniae exhibit a weak EPR signal with g approximately equal to 5. Temperature dependence of the signal was consistent with an S = 3/2 system with negative zero-field splitting, D = -5 +/- 0.7 cm-1. The ms = +/- 3/2 ground state doublet gives rise to a transit...

Bell pepper is an important vegetable crop containing lots of bioactive compounds. The present study was designed to improve the productivity and quality bell with application arbuscular mycorrhizal fungi (Rhizophagus irregularis) plant growth-promoting bacteria (Azotobacter chroococcum) in a combination chemical fertilizer. Five treatments consisted 75% fertilizer (T1), 100% (T2), + R. irregul...

The chelating agents EDTA, o-phenanthroline, nitrilotriacetic acid (NTA), ethylenediamine-bis(o-hydroxyphenylacetic acid) (EDDA) or dimethylglyoxime prevented the expression of hydrogenase activity in batch cultures of nitrogen-fixing Azotobacter chroococcum, but did not inhibit preformed enzyme. The inhibition was reversed either by adding a mixture of trace elements (Cu2+, Mn2+, Zn2+, Co2+) o...

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azotobacter is a gram negative, aerobe, chemo-organotroph with the, polymorphism including rod, cocci and ovoid forms. this bacterium belongs to gama-proteobacteria class, pseudomonaceae family with 7 species. it cannot produce spores but forms cyst. azotobacters’species lives in different regions from tropicals to poplars in ph 3-9. however, it can be fined mainly in alkaline and natural soils...