Preparation of white rot fungal inoculum and its application to bioremediation of chlorimuron-ethyl-contaminated soil.

ABSTRACT

Chlorimuron-ethyl is currently the primary herbicide used for chemical weed control in a soybean field. In this study, a solid microbial inoculum (corn stalk-white rot fungus (W-1)) was prepared for the remediation of farmland soil contaminated by chlorimuron-ethyl. Firstly, the preparation method of the microbial inoculum was studied. Secondly, the degradation rate of the chlorimuron-ethyl in the ground by the solid microbial inoculum is improved by optimizing the proportion of the protective agent. Then the effects of applying solid microbial inoculum, free bacteria and corn straw on the degradation rate of chlorimuron-ethyl in soil were weighed. Finally, Illumina MiSeq sequencing was used to measure the composition and diversity of bacterial and fungal communities in the ground before and after using microbial inoculum. The degradation rate of chlorimuron-ethyl in soil by solid microbial inoculum was 84.87% after 20 d using corn straw as the support, room temperature drying, 4% Ca3(PO4)2 as the protective drying agent, and 1%(w) dextrin as the ultraviolet protective agent. Inoculation of white rot fungi could significantly affect the community structure of bacteria and fungi in the soil, making the chlorimuron-ethyl degrading communities become the dominant communities and playing an essential role in the degradation of chlorimuron-ethyl. The results showed that using solid microbial inoculum was an effective way to repair farmland soil polluted by chlorimuron-ethyl.