Isolation and identification of phthalate-degrading bacteria and their characteristics

Abstract:

In order to implement the bioremediation on the phthalate contaminated soil, seven bacteria strains D1-D7, which can use phthalate mixtures as the sole source of carbon and energy, were isolated from constructed wetland soil. The morphological, physiological and biochemical characteristics of the strains were studied. Strains D1 and D2 were identified as Pseudomonas sp., strain D3 as Enterobacter sp., the others as Rhodococcus sp., based on the 16S rRNA gene sequence analysis. The batch test results showed that all of the strains could degrade phthalate in three days effectively, the degradation efficiencies of DMP, DBP and DEHP were above 65％, 60％ and 30％ respectively. The degradation efficiency decreased with the increasing of phthalate alkyl chain length. The D1-D7 strains all grew with phthalic acid as the sole source of carbon and energy. The utilization of phthalic acid was 18％-39％, which showed that the phthalate could be thoroughly degraded by strains D1-D7 through phthalic acid metabolism pathway.