Microbial isolates are isolated from 25 agricultural soil samples contaminated by
herbicide. Their ability of degradation atrazin and 2,4-D herbicides are
examined . Two isolates are chosen according to ability for degradation , then
isolated and identified by using numbers of culture media and biochemical tests
Results have indicated that the bacteria are Escherichia coli (B6) and
Pseudomonas fluorescens (B13) , which have been incubated with a number of
herbicides concentrations (5.0 -17.5) mg L-1 from atrazin and (5.0 -20.0) mg L-1
from 2,4-D.
Results have shown the degradation increases with increasing the concentrations
(65 ، 60)% for isolate B6 , B13 respectively with 12.5 mg L-1 of atrazin and (73،
61)% of 2,4-D with 15.0 mgL-1 of atrazin and (73،61) % of 2,4-D with 15.0
mgL-1 after five days incubation.Chemical mutagen (Nitrosoguanidine) 500 μg
mL-1 used to mutant bacteria cell with time (0.5 , 1.0 , 1.5 and 2.0) hr. one hour
is enough to do that , there fore rasio degradation increases (93 , 89) % Atrazin
of (B13C6 , B6C3) respectively in 12.5 mgL-1 and (97 , 93) % , 2,4-D in 15.0
mgL-1 . Achridin orange and sodium Dodecyl sulphate (SDS) are used to curined
bacteria plasmids by 2500 μg mL-1 from (SDS) and 200 μg mL-1 from (Achridin
orange). The results show (B13C6 , B6C3) became curing cells.