Abstract:A microcosm incubation experiment was conducted to study the effects of bacteria-feeding nematodes, which feed phenanthrene-degrading bacteria (Pseudomonas putida),?on phenanthrene removal from the un-sterilized soil. Phenanthrene was?selected as?a?model of aromatic hydrocarbon (PAH). The factorial experimental design include four treatments, i.e., soil inoculated with bacteria only (B), bacteria-feeding nematodes only (N), both B and N (BN), and neither B nor N (CK). Soil was sampled destructively at 0 d, 5 d, 14 d and 28 d after the initiation of incubation. Selected indices include the residual concentrations of phenanthrene, the abundance of bacteria-feeding nematodes and enzyme activities of the catalase, hydrolysis rate of fluorescein diacetate (FDA). The results demonstrated that bacteria-feeding nematodes inoculated only (N) treatment stimulated phenanthrene removal during the incubation period of 0-14 days, however, the stimulation of BN on phenanthrene removal increased gradually, especially obvious at later incubation period (14-28 days). At the end of the incubation period, the sequence of phenanthrene removal was: BN (48.15%)>B (45.06%)>N (44.43%)>CK (43.52%). The results also showed that the inoculation of bacteria-feeding nematodes could significantly (p<0.5) increase bacteria and soil enzyme activities with the incubation time. In conclusion, the interaction between bacterial-feeding nematodes and bacteria could possibly accelerate phenanthrene degradation in soil.