Isolation, Selection and Identification of Nitrogen Fixation Rhizospheric and Endophytic Bacteria from Maize (Zea Mays L.) Grown on the Soil

Abstract— N-free medium (Nfb, LGI and Burks) were used to isolate bacteria having nitrogen fixation characteristics. Quantitative measurement by colorimetric methods helped to select the best isolates of nitrogen-fixing and IAA biosynthesis. The result of isolation was a total of 30 rhizopheric and 150 endophytic isolates having the both abilities. Sixty isolates having good biofertilizer activity were chosen to study. Isolates strains have both nitrogen fixation produced indole-3-acetic acid (IAA) in vitro. Six selected isolates had 16S rDNA sequences similarities with bacterial strains in data of GenBank with the values ranging between 94% and 99% of similarity in which includes strains of Enterobacter ludwigii DNL14, Enterobacter kobei DNT5, Bacillus pumilus DBT4, Klebsiella pneumoniae DNR5, Lactobacillus plantarum DLR6, Pseudomonas nitroreducens DND5. Especially, strains of endophytic isolates root maize origin as Klebsiella pneumoniae DNR5 biofertilizer activities synthesized average highest as NH4 (5.64 mg/L) and IAA (5.29mg/L) which can be exploited for enhancing soil fertility and plant growth.