Immobilization of combined bacteria and its degradation of pyrene and benzo[a]pyrene in contaminated soil

A strain autochthonous fungus and a strain bacterium identified as Bacillus sp. and Mucor sp. were isolated from a contaminated soil and their co-immobilization was studied. The co-immobilization carrier and the method was investigated, which could after screening degrade pyrene (Pyr) and benzo[a]pyrene (BaP) in the contaminated soil efficiently. The results show that the optimumal immobilized carrier was modified vermiculite, and better mass transfer and could degrade 94.96% and 74.96% of Pyr and BaP respectively in 42 days, which was remarkably higher than the degradation rate of that by the free strains. The microstructure of immobilized mixture microorganism was observed by scanning electron microscope (SEM). Also, the process of the transmission in soil was discussed.