The unexpected effect of compound microbial agent NP-M2 on microbial community dynamics in a nonylphenol-contaminated soil: the self-stability of soil ecosystem

This study analyzed the promotion of NP degradation with the addition of an external functional complex microbial agent (NP-M2) at different concentrations (50 mg/L and 200 mg/L) and investigated the effects of NP-M2 application on soil microbial community variation. Both Indigenous microorganisms (TU50 and TU200 treatments) and microbial agent application (J50 and J200 treatments) removed soil NP rapidly (93.10%-98.98%); microbial agent addition accelerated the NP degradation rate because there was no significant lag period. The S-CAT, S-SC, and S-PPO were the key environmental factors influencing the bacterial community structure and taxon distribution. Different treatments had little effect on soil bacterial α-diversity but significantly affected the bacterial community composition and β-diversity. In general, major bacterial community shifts were caused by NP concentration and, to a lesser extent, by the microbial agent NP-M2. In conclusion, NP-M2 promoted NP remediation to a certain extent in contaminated soil, but further research is still required to determine the possibility and controllability of its stable performance in soil.