Adsorption-Degradation of Polycyclic Aromatic Hydrocarbons in Soil by Immobilized Mixed Bacteria and Its Effect on Microbial Communities

The combined action of biosorption and biodegradation can achieve a remarkable reduction of organic pollutants. In this study, Pseudomonas sp. SDR4 and Mortierella alpina JDR7 were selected as the representative microorganisms to investigate adsorption and degradation of polycyclic aromatic hydrocarbons (PAHs) in soil using immobilization technology and the subsequent change of the microbial community structure. The results showed that the adsorption capacity of immobilized carriers was much higher than that of dead microorganisms and that the addition of dead microorganisms did not affect the adsorption characteristics of immobilized carriers. The chemical reaction was the major factor controlling the adsorption rate of PAHs in sterilized soil (CK), nonsterilized soil (CK-1), and soil amended with dead body immobilized JDR7 and SDR4 mixed bacteria (MBD). The growth and metabolism of Pseudomonas sp. SDR4 and M. alpina JDR7 are the main reason for enhanced PAH degradation in the soil amended with living body immobilized JDR7, SDR4 mixed bacteria (MB).