Screening And Composition Analysis Of Carbendazim-degrading Bacterial Communities And Their Degradation Effect

Carbendazim is a spectrum fungicide, which can effectively combat a variety of crop diseasescaused by fungi. The use of carbendazim in China is extensive, but the residue can cause liver diseaseand chromosomal aberrations, and have a certain toxic effects on mammals. On the carbendazim residueissue, this paper screened efficient degrading bacterial communities and strain, analyzed the bacterialcommunities composition, identified the taxonomic status of the new strain, studied the affect made bythe add xenobiotics to degradation ability of carbendazim degradation bacterial communities and strain,and evaluated the degradation ability of degradation bacterial communities and strain in soil. Asfollows:The degradation bacterial communities screened and strain isolated: After the enrichmentculture, from the tested22samples, screened nine bacterial communities having carbendazimdegradation ability. In the15d, in the culture medium contenting600mg/L carbendazim, the bacterialcommunities having more than50%degradation capacity are DJL-161, DJL-164, DJL-165, DJL-166and DJL-167. From the degradation bacterial communities isolated forty-six strains and screened fivestrains with the ability of carbendazim degradation, in the15d, in the culture medium contenting600mg/L carbendazim, the strains having more than50%degradation capacity are DJL-111-3,DJL-165-2, DJL-166-2and DJL-167-4.The composition of the degradation bacterial communities and strain identification: Thebacterial communities analysis showed that, some bacterial communities of the screened carbendazimdegradation bacterial communities have the same strain, also showed that the same strain compositionin these bacterial communities also have significant differences. One bacterial communitiesh whichbelongs to the Pseudomonas species (Pseudomonas sp.) exist in DJL-96, DJL-165, DJL-166, DJL-167,DJL-171and DJL-172. By the comparative analysis of the bacterial communities and strain, it can bedrawn that the screened strain from the bacterial communities is not necessarily the most predominantstrain of the bacterial communities. The five strains with carbendazim degradation ability, such asDJL-111-3, DJL-161-4, in addition to DJL-161-4being identified of oligotrophic Aeromonas spp(Stenotrophomona sp.), the remaining four strains were identified of Rhodococcus is (Rhodococcus sp.).The strain distribution is more concentrated, mainly distributed in the Rhodococcus genus(Rhodococcus sp.).The influence of exogenous organic made to carbendazim degrading:The degradation effect onbacterial communities of promoting agent306, promoting agent501, promoting agent502andpromoting agent503are apparent promoting; the accelerator301,303,305,ammoniumchloride,arginine and γ-aminobutyric acid play a significant inhibitory effect the bacterial communitiesdegradation effect Some sugars and amino acids play a promoting role for the degradation effects of thedegrading strains; most of the organic acids and phenols play an inhibitory effect on the degradationeffects of carbendazim-degrading bacteria. The degradation ability of carbendazim degrading bacterial communities and strain in soil:The results showed that, in the soil containing of5mg/kg carbendazim, the carbendazim degradationability of strain are higher. At72h, in the soil containing of5mg/kg carbendazim, the strains whosedegradation rate are more than95%are DJL-111, DJL-161, DJL-164, DJL-165and DJL-171; the strainwhose degradation rate is more than95%is DJL-111-3.