bioremediation of certain organophosphorus pesticides by two biofertilizers, paenibacillus( bacillus) polymyxa (prazmowski ) and azospirillum lipoferum (beijerinck)

continuous and excessive use of organophosphorus compounds has led to thecontamination of water and soil ecosystems. the degradation of organophosphorusinsecticides, chlorpyrifos, chlorpyrifos- methyl, cyanophos and malathion in mineral saltsmedia were studied. the effect of additional biofertilizers, singly or combined withorganic amendments, on chlorpyrifos and cyanophos degrading activity in soil wereinvestigated. paenibacillus ( bacillus) polymyxa (prazmowski ) and azospirillum lipoferum(beijerinck) were found to degrade the organophosphorus insecticides, chlorpyrifos,chlorpyrifos- methyl, cyanophos and malathion in mineral salts media as a carbon andphosphorus source. paenibacillus ( bacillus) polymyxa (prazmowski ) appeared to be moreeffective than azospirillum lipoferum in degrading all the tested organophosphatepesticides in mineral salts media. the half-life values (t1/2) of chlorpyrifos, chlorpyrifos –methyl , cyanophos and malathion were found to be undetectable , undetectable , 2.4, andundetectable days in mineral salts media inoculated by paenibacillus ( bacillus) polymyxa(prazmowski ),while they reached 1.6, 0.1, 5.2, and 0.8 days by azospirillum lipoferum(beijerinck) compared to 4.4, 1.8, 8.8, and 1.4 days in non-inoculated mineral salts media.chlorpyrifos and cyanophos degraded in soil samples inoculated by azospirillumlipoferum (beijerinck) plus peat- moss more rapidly than in the other treatments. dualinoculation of azospirillum lipoferum (beijerinck) and paenibacillus ( bacillus) polymyxa(prazmowski ) improved the rate of degradation of chlorpyrifos and cyanophos in soil.azospirillum lipoferum (beijerinck) appeared to be more effective than paenibacillus (bacillus) polymyxa (prazmowski ) in degrading soil-applied chlorpyrifos and cyanophos.these results highlight the potential of these bacteria to be used in the clean- up ofcontaminated pesticides – waste in the environment.