Different Methods for Isolation and Preliminary Identification of Azotobacter




Plant growth promoting rhizobacteria (PGPR) are known to influence plant growth by various direct
or indirect mechanisms. Thirty–two strains were isolated from 15 soils sampled in central Iran, by
using and comparing three different methods. The screening of soil samples by means of soil paste–
plate method combined with isolation on mannitol agar proved to be the best strategy in terms of
reliability and selectivity. These test isolates were biochemically characterized. These isolates were
screened in vitro and identified by using BIBI(Bioinformatics Bacterial Identification Tool). BIBI was
designed to automate DNA sequence analysis for bacterial identification in the different fields. BIBI
relies on the use of BLAST and CLUSTAL W programs applied to different subsets of sequences
extracted from GenBank. These sequences are filtered and stored in a new database, which is adapted
to bacterial identification.