Abstract: Resin, due to its extreme difficulty to be degraded in nature, plays an essential role during the remediation of petroleum-contaminated soil. Resin has high environmental risks since it could accumulate long time in the environment. Functional groups in resin structure such as aromatic nucleus and carboxyl groups are hard to be degraded. Consequently, degradation rate is not enough to indicate the effect of remediation. MicroResp^TM method can be used to assess soil community level physiological profiles, which is an important index reflecting the effect of remediation. In this study, resin obtained from Liaohe oilfield and superior mixed bacteria were prepared for the remediation. There were four treatments, including bioremediation (Bio), electrokinetic-bioremediation (EK+Bio1), electrokinetic-bioremediation with nutrient matters (EK+Bio2) and discontinuous electrokinetic-bioremediation (EK+Bio3). The results showed that the average degradation rate varied among different treatments, with an order of EK+Bio2>EK+Bio3>EK+Bio1>Bio. The highest degradation rate was 9.82% (for EK+Bio2), which was 3.06 times of that Bio (3.21%). The abundance of microorganisms increased after remediation, the trend of which was similar to the degradation rate of resin. The results of MicroResp^TM analysis showed that the microbial metabolism and microbial activity were promoted. Microorganisms had selectivity of carbon sources under different remediation approaches. The ability of microorganisms to metabolize saccharides substantially increased. In conclusion, electrokinetic-bioremediation could promote the degradation of resin as well as enhance the physiological profiles of soil community.

Key words: drought stress, abscisic acid, Machilus yunnanensis